Exactly. No federation list, only members in the advisory comities and whatever.
Discussion
Those members are functionaries, aka signers, as far as I understood. That is what they mean by "expanding the federation".
It is curious though, that a proper list (other than all the logos in the image I linked earlier) indeed does not seem to exist.
OTOH, it's not like they are keeping the members hidden, or the size of the federation, you can find this in their blog posts over time.
They may announce some of them, but there’s no authoritative list - I assume if some leave it won’t be announced. Also no idea what the required threshold is.
Perhaps nostr:npub1jg552aulj07skd6e7y2hu0vl5g8nl5jvfw8jhn6jpjk0vjd0waksvl6n8n could clarify.