Most files are LGPL anyway by now. contribute.md still requires
contributors to provide changes under LGPL, which should cover changes
to files that are LGPL, as well as GPL files.
I guess there is a hard to balance tradeoff between appearing rude or
dismissive, and making the user think it's ok to not provide essential
information.
I do not understand why github requires adding this crap to source code
repositories themselves, instead of making them part of the repository
configuration. Remove CONTRIBUTING.md to compensate for github crap
accumulating.