Not anymore, we are fully community-driven. At least there is not a single maintainer working at Meta. And of that list, I believe only @cristianoc at some point worked for Meta.
The creator of BuckleScript/ReScript himself (@Hongbo) worked at Meta for some time, as well as some others.
Meta used to develop Facebook Messenger in BuckleScript with ReasonML syntax, later in ReScript, but it seems they now double down on flowtype instead.
