It depends on the bridge. Some bridges you might use without being aware. E.g. a public open source room/channel that is bridged between matrix and libera.chat.

It depends on the bridge. Some bridges you might use without being aware. E.g. a public open source room/channel that is bridged between matrix and libera.chat. You just use either IRC or Matrix and interact with other users without caring what protocol they use to access the room.