Earlier quoted context omitted.
"I assumed the license was OK considering its popularity." Always check the licence. Public domain, MIT, simple, plain BSD, GPL (any version), apache - if it's anything else, be extremely cautious.
> Public domain There are jurisdictions that don't recognize PD grants. I can't think of a good reason to use CC0 over MIT or BSD. > GPL (any version) This might be doctrinaire but I won't use the (L)GPLv3 because of the AGPL linking clause: > Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Publ…
There's also the Zero-clause BSD License https://spdx.org/licenses/0BSD.html which is the same kind of thing except it does not even mention the words "public domain".