tip: if you’re interested in running a homeserver, mautrix-discord lets you use it as a Discord client (note that this is against Discord ToS, so don’t puppet a valuable account; however, I’ve been using it fine since February with only one forced password reset from catching up after a long downtime)

From your image, only the second (and perhaps the fourth) entries are related to [matrix], and the second entry is only related to matrix.org specifically. Matrix (often stylized as [matrix]) is a protocol, not a server.