Website .well-known directory
IANA
RFC8615
defines a “.well-known/” folder for web servers to put metadata fundamental to a web server’s organization, policies or contact information.
Several popular files are seen under public website https://example.invalid/.well-known/
directory.
keybase.txt verifies ownership of domain for Keybase.io. security.txt gives security incident contact info. dnt-policy.txt contains the Do Not Track Policy statement. humans.txt is for author information.