For instance, in Github, can we declare our own license (in LICENSE.txt): "make any use only if you declare the author", or must we choose known ones like GPL3, MIT, etc
Second, you need to pay a lawyer to write your own license. AFAIK, the CECILL license required more than a full time year of work to several lawyers. Law is as difficult as programming (and perhaps even more).
Then, if you invent your license, you'll need to negotiate and convince organizations like FSF, OpenSource initiative, APRIL, AFUL to label your license as open source and compatible with existing ones....
In practice, if you invent your license, nobody will use your software
(in a professional setting). In many corporations, it is managers and lawyers who dictate what open source licenses developer can use (even to link an existing open source library).
Please read also this paper on the simple economics of open source.
So make us a favor: don't publish your software with your own license. You'll avoid losing your and perhaps our time.
I speak of personal experience, being paid to write free software. The most difficult issue is to find real users.
PS. Since you live in France, consider joining AFUL or APRIL -I am member of both- and look into Systematic GTLL. Read J.Tirole's book Économie du Bien Commun (it has a long chapter dedicated to open source software), look online into X.Leroy talks at Collège de France, Roberto DiCosmo website, the Software Heritage initiative, follow Séminaire Code Source, and see RefPerSys. If you want to, please send me an email to
[email protected] mentioning the URL of your question.