The original Raspberry Pi Foundation / Trading license:

These design files are made available openly, with no limitations.

Permission to use, copy, modify, and/or distribute this design for

any purpose with or without fee is hereby granted.

THE DESIGN IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

WITH REGARD TO THIS DESIGN INCLUDING ALL IMPLIED WARRANTIES OF

MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE

FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY

DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER

IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING

OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS DESIGN.

Which looks rather like the UnLicense:

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or

distribute this software, either in source code form or as a compiled

binary, for any purpose, commercial or non-commercial, and by any

means.

In jurisdictions that recognize copyright laws, the author or authors

of this software dedicate any and all copyright interest in the

software to the public domain. We make this dedication for the benefit

of the public at large and to the detriment of our heirs and

successors. We intend this dedication to be an overt act of

relinquishment in perpetuity of all present and future rights to this

software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR

OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <https://unlicense.org>