[3np]

> Can Irssi be used to access this matrix thing?

Yup. I haven't tried it myself and I think there are different ways to set that up but this could be a start (I think this is more targeted towards bridging matrix and IRC, which may or may not be what you want): https://matrix.org/bridges/#irc

> If not, is there some nice matrix command line client in the Debian repos?

Not sure what's in the mainline debian repos but there are some decent CLI clients, yes: https://matrix.org/clients/

If you're OK with weechat you can use that already :)

IMO matrix is already mature to be an IRC killer (caveat federated/decentralized identities, if that's something you require but arguably IRC doesn't have that either).

[kzrdude]

Can you explain the caveat? Federated identity seems to be what matrix already offers. Even if the main instance at matrix.org dominates.

[3np]

Federated/decentralized identity is on the roadmap and being worked on - while yes, Matrix conversations and discovery are fully decentralized and federated, each account is still tied to a single homeserver through the domain (e.g. [e-mail] still depends on the matrix.org homeserver to use their identity)

Arguably none of the alternatives have this quality either but I find it worth pointing out as a requirement for next-generation IM.

[Arathorn]

https://github.com/matrix-org/matrix-doc/blob/neilalexander/... is the latest work on this ftr :)