I agree it's not immediately clear how it works, although I think I understand the role it's intending to fill.
If you're not familiar with the distinction between git and github it could be even more confusing.
As soon as I hear decentralized I have lots of questions about the underlying protocols. Their protocol page helps a little but also uses terms I'm not familiar with like "gossip protocol".
It would be nice for there to be a page that motivates the project a bit more, ie. explaining the technical problems they are attempting to solve before enumerating the components of the complex system they've built.
Someone looked at git - a distributed version control system that already works, that has been working since 2005, that Linus Torvalds wrote in a fit of pique and spite, and that currently hosts approximately all of the world's source code - and said, "This is good, but what if we added BitTorrent?" And then, presumably after consuming substances that I cannot legally inquire about, they continued: "And what if we added the Bitcoin peer-to-peer protocol?" And then, reaching a crescendo of architectural ambition that would make Icarus say "maybe dial it back a little," they concluded: "And we should DEFINITELY add blockchain identity."
Notice how each additional sentence makes the previous sentence worse, like a turducken of solutions looking for problems, or a nesting doll where every layer is a different kind of sadness. This, I presume, is what happens when you have a hammer and a screwdriver and a chainsaw, and you decide that every problem would be better solved by using all three simultaneously while riding a unicycle.
But seeing as it already does exist, it's pretty awesome.