21 files changed, 189 insertions, 210 deletions
diff --git a/catbird/asset.scm b/catbird/asset.scm
index 71d9b6a..f250e80 100644
--- a/catbird/asset.scm
+++ b/catbird/asset.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/cached-slots.scm b/catbird/cached-slots.scm
index 22ab00d..bb786e9 100644
--- a/catbird/cached-slots.scm
+++ b/catbird/cached-slots.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/camera.scm b/catbird/camera.scm
index 90120b7..a3d8fd3 100644
--- a/catbird/camera.scm
+++ b/catbird/camera.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/config.scm b/catbird/config.scm
index 4a57c52..98ad030 100644
--- a/catbird/config.scm
+++ b/catbird/config.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/inotify.scm b/catbird/inotify.scm
index fc170f5..332ed7f 100644
--- a/catbird/inotify.scm
+++ b/catbird/inotify.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/input-map.scm b/catbird/input-map.scm
index dc3bd85..9c11677 100644
--- a/catbird/input-map.scm
+++ b/catbird/input-map.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/kernel.scm b/catbird/kernel.scm
index 413e1b4..01861cf 100644
--- a/catbird/kernel.scm
+++ b/catbird/kernel.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/line-editor.scm b/catbird/line-editor.scm
index d6aac0a..b991f47 100644
--- a/catbird/line-editor.scm
+++ b/catbird/line-editor.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/math.scm b/catbird/math.scm
index cca718d..3f16418 100644
--- a/catbird/math.scm
+++ b/catbird/math.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2023 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/minibuffer.scm b/catbird/minibuffer.scm
index 197b695..d4c1a5f 100644
--- a/catbird/minibuffer.scm
+++ b/catbird/minibuffer.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/mixins.scm b/catbird/mixins.scm
index 75e6d50..3945aab 100644
--- a/catbird/mixins.scm
+++ b/catbird/mixins.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/mode.scm b/catbird/mode.scm
index d0d45ac..c238cd1 100644
--- a/catbird/mode.scm
+++ b/catbird/mode.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/node-2d.scm b/catbird/node-2d.scm
index d7a81e8..2ba7b7c 100644
--- a/catbird/node-2d.scm
+++ b/catbird/node-2d.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/node.scm b/catbird/node.scm
index 277c611..2553ba3 100644
--- a/catbird/node.scm
+++ b/catbird/node.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/observer.scm b/catbird/observer.scm
index 1408fc2..f7a2628 100644
--- a/catbird/observer.scm
+++ b/catbird/observer.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/overlay.scm b/catbird/overlay.scm
index 2b3c184..5c3cf17 100644
--- a/catbird/overlay.scm
+++ b/catbird/overlay.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/region.scm b/catbird/region.scm
index f42532a..af6f206 100644
--- a/catbird/region.scm
+++ b/catbird/region.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/repl.scm b/catbird/repl.scm
index 5619c9a..c08ef20 100644
--- a/catbird/repl.scm
+++ b/catbird/repl.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/ring-buffer.scm b/catbird/ring-buffer.scm
index 7632c2c..f181224 100644
--- a/catbird/ring-buffer.scm
+++ b/catbird/ring-buffer.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/scene.scm b/catbird/scene.scm
index 445a66c..a1bcffa 100644
--- a/catbird/scene.scm
+++ b/catbird/scene.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;
diff --git a/catbird/ui.scm b/catbird/ui.scm
index 3323725..19401e4 100644
--- a/catbird/ui.scm
+++ b/catbird/ui.scm
@@ -1,18 +1,17 @@
 ;;; Catbird Game Engine
 ;;; Copyright © 2022 David Thompson <davet@gnu.org>
 ;;;
-;;; Catbird is free software: you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation, either version 3 of the License, or
-;;; (at your option) any later version.
+;;; Licensed under the Apache License, Version 2.0 (the "License");
+;;; you may not use this file except in compliance with the License.
+;;; You may obtain a copy of the License at
 ;;;
-;;; Catbird is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;;; General Public License for more details.
+;;;    http://www.apache.org/licenses/LICENSE-2.0
 ;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with Catbird.  If not, see <http://www.gnu.org/licenses/>.
+;;; Unless required by applicable law or agreed to in writing, software
+;;; distributed under the License is distributed on an "AS IS" BASIS,
+;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+;;; See the License for the specific language governing permissions and
+;;; limitations under the License.
 
 ;;; Commentary:
 ;;