[frabbit]

Also: what do we know about the people and institutions developing and promoting these standards and implementations?

We've seen the appointment of people with biographies suggesting affinity with US interests, for example Katherine Maher to the Signal Foundation (and the departure of the Moxie Marlinspike.)

I see a members list for the board overseeing the spec for Matrix, but does anyone know who they are[1]? And the spec is one thing, but who controls the development of the actually used clients and implementations?

Please note I am not imputing anything w.r.t. Matrix/Element etc, but if we're bothered to put effort into E2EE then it is probably worth thinking about this aspect in addition to whether the technical basis is sound. The historical record is clear on government attempts to influence things from that end.

I have the same sort of worries about GnuPG (and the SPoF that is the hard-working maintainer.)

Maybe E2EE is not of concern to the OP, in which case disregard the above.

1. https://matrix.org/foundation/governing-board-elections/