In the language of Polandball comics, it means “give land/territory”.

“Gib” is taken from the German imperative for “give!”

Best theory is that “clay” as “land” originates from a bad machine translation.

It seems somene created a Wiki that covers these terms: https://www.polandballwiki.com/wiki/Terminology#Clay

Synology’s DSM has built-in MFA support, though it also has some features for external identity management. I don’t think Keycloak and so on would be compatible though.