The current interface for server location plugins is old and hasn't kept up with changes. In particular, there is no support for HTTPS endpoints, plugins must perform their own DNS, and the number of servers that can be returned is opaque. Among other things, this would enable sssd to use URI records from DNS for Kerberos/IPA discovery (https://pagure.io/SSSD/sssd/issue/3533), which would in turn allow sssd/freeIPA to not require ports 88 and 464 to be open.
Clearing out tracker of things that aren't likely to happen soon, but this remains on my todo list tracked elsewhere.