The Matrix.org Foundation on Nostr: npub1u25cz…zu0j0 threads were added to the matrix spec in 1.4: ...

npub1u25czl2n658suzwlf3tjhyjehmwnnts3swmf05s78cna3pjxa2qs8zu0j0 (npub1u25…u0j0) threads were added to the matrix spec in 1.4: https://spec.matrix.org/unstable/client-server-api/#threading. EX will presumably support them eventually, but is still being built.