Back when Let’s Encrypt started giving out free SSL certificates, one bit that visible all over the web was the “well-known” directory. I never thought much about it – it’s just a name after all.
Turns out, there is actually an RFC 5785 that defines a standard for the well-known uniform resource identifiers (URIs). And that’s a lot more generic than just the bit that Let’s Encrypt needs.
Accidentally stumbled upon this while reading “A Well-Known URL for Changing Passwords” draft.