Based on this open issue on the repo [0], it only has federated timeline support. The lead developer of Mastodon had this to say with regards to not adding it to iOS[1]:
> The omission is intentional and I do not intend to add these types of timelines into the app. They might have made sense for early Mastodon in November 2016 when there were less than 20k people total and all from a homogenous demographic but nowadays the signal to noise ratio makes them a liability in almost every aspect.
> [...]
> The local and federated timelines are not going away from other apps or the web app, to be clear. I’m simply not adding them to this app, and if that bothers you, simply don’t install the app.
This saddens me, and I truly believe it's because Mastodon's author, Eugen, also runs the largest server, mastodon.social. Of course the local timeline there is utter chaos, basically like the Twitter firehose. That's absolutely not the case for topical servers, like ones that specialize in posts about cats, or a friend group, or a particular city. I don't think Eugen opposes the idea out of malice, because he seems like a pretty good guy. I think he just has a particularly narrow view of what Mastodon is, as seen from his perspective.
> This will continue to limit its opportunity for wide adoption.
I don't see this having any practical effect. Unlike other services, you aren't locked into one app. There are others, and perhaps more importantly, they were here first.
