Tor also, in the early days.
i don't think it matters that much, this isn't exactly a long list. qubes doesn't work on most hardware. wireguard is ridiculously elementary in what it does, literally just elliptic curve keys and ECDH, same stuff used here in nostr.
signal was probably developed by intels. it was originally called "red phone" and was the first chat system binding to mobile phone numbers and using the mobile network (SMS) as a back channel to pass shared secrets, iirc - or something like that, maybe it was just for a rendezvous.
