Wild guess.
Every service has a different url to publish the proof.
The external networks will never agree to a standard so it's up to nostr to develop each proof individually?
Discussion
What are the necessary elements? URL and signature/proof? Could these by set up by the user? A friendly template to make standards would not only make proofs app-agnostic but also more censorship-resistant and upgradable (who knows if gits access or specs change some day). Is this an impossible or a bad idea?
Do you have examples of other services that would make sense to make proof against from your nostr profile?
Sure.
Peertube, Gitlab, Blockchain info, your personal blog or website, OBSD SVN, IEEE explore, Pixelfed, Wikipedia, Wikitionary, Commons, XDA, Stack Overflow, Arch Package Maintainers Directory, pine64 forum, Federal Bar List of Attorneys, w3c Working Group Chairs Personal Profile, arXiv, Bitcoin...
But even if you just consider these 3 tomorrow f.i. gists can change or require special access, which would make more suitable to publish the proof in other way.
Is it an imposible task to abstract a template to create standards? Otherwise I think I'd simply get rid with a field for links plus a "verify this proof by yourself clicking here". Maybe I'm wrong though.
It is not clear on how to create the proof. Did you find a way?