The acct URI scheme is a proposed internet standard published by the Internet Engineers Task Force, defined by RFC 7565. The purpose of the scheme is to identify, rather than interact, with user accounts hosted by a service provider. This scheme differs from the DNS name which specifies the service provider.
The acct URI was intended to be the single URI scheme that would return information about a person (or possibly a thing) that holds an account at a given domain.
References
Acct (protocol) Wikipedia(Text) CC BY-SA