youronlyone on Nostr: I'm not sure what the context is, re: Mastodon software. But to answer your question, ...
I'm not sure what the context is, re: Mastodon software. But to answer your question, as long as the Mastodon software an instance/server is running on has #ActivityPub enabled (thus connected to the larger #Fediverse ), then you can follow an account running on #Mastodon software.
If you want to follow any fediverse account outside of the ActivityPub/fediverse network, the user has to opt-in to a bridge like #BridgyFed (see: https://fed.brid.gy ). It doesn't matter if they are using the Mastodon software or not, following and/or sharing between networks using different protocols require a “bridge” (or “translator” from one protocol to another).
As for your question if you can use #RSS if what you meant was “Feed”, then yes, as far as I know, all mature Fediverse software provides a Feed for each account, and that includes Mastodon itself. Though I think you should make sure your Feed Reader understands #Atom as well, as that's the primary spec being used even though the feed ends with “.rss” (AFAIK).
If you want to follow any fediverse account outside of the ActivityPub/fediverse network, the user has to opt-in to a bridge like #BridgyFed (see: https://fed.brid.gy ). It doesn't matter if they are using the Mastodon software or not, following and/or sharing between networks using different protocols require a “bridge” (or “translator” from one protocol to another).
As for your question if you can use #RSS if what you meant was “Feed”, then yes, as far as I know, all mature Fediverse software provides a Feed for each account, and that includes Mastodon itself. Though I think you should make sure your Feed Reader understands #Atom as well, as that's the primary spec being used even though the feed ends with “.rss” (AFAIK).