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.
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.
> Radicle is a peer-to-peer code collaboration platform (“forge”) built on Git.
-----
> Why Git/GitHub are used as if they were the same category of things?
They are not. Github is a centralized collaboration platform built on git, and radicle is a peer-to-peer collaboration platform built on git.
-----
> Wtf is "forge"?
A word some people started using for the class of Github/Bitbucket(RIP) or even Fossil-type things, as FOSS alternatives began to multiply.
-----
> Radicle is an alternative... to what?
To Github, or other "forges."
Then why do they bring Git into the picture? They are not comparing themselves to Git...
> Radicle is a peer-to-peer code collaboration platform (“forge”) built on Git.
This is a word salad that means nothing... more than 99% of moderns software is built on Git in one way or another. Anything that is designed to be used by more than a single user could be arguably called a "collaboration platform". This description completely fails to describe anything useful about the program they are trying to describe. For instance, Git is a peer-to-peer code collaboration platform built on Git. And the same can be said about a huge number of programs that share very little in terms of purpose or application.
When someone writes a definition, s.a. you'd find in encyclopedia, the rule is that it has to (a) link to the broader category of things (b) specify in what way the subject is (mostly) unique in the category (a). If you give only (a), then the reader walks away wondering how is subject different from anything else in (a). If you only give (b), then the reader needs to guess (a), and if they fail, they may misattribute or simply abandon efforts to understand the subject.
This attempt at "definition" is the textbook example of forgetting the (b). It's something that a 10-12 y.o. could come up with... this is not what an adult should strive for.
> They are not. Github is a centralized collaboration platform built on git, and radicle is a peer-to-peer collaboration platform built on git.
You didn't understand the question.
Edit:
Breaking down the “word salad”:
> Radicle is a peer-to-peer code collaboration platform (“forge”) built on Git.
Peer-to-peer: it functions with individual nodes on the network spreading state for tracking it without relying on a single entity or centralised service.
Code collaboration platform (forge): you use it not just to store code but provides a way to keep track of “patches” (their term for PRs) and issues, amongst other things, to enable multiple people to collaborate on a code base
Built on git: the technology runs on top of git insofar as not only is the VCS just git, but the issues, patches, etc are stored in git. So the project isn’t merely developed using git, but when running the tool yourself it’s still backing everything under git.
I hope the definitions shared in the sibling comment will help.
> Then why do they bring Git into the picture? They are not comparing themselves to Git...
I would find it very strange if Github didn't mention git. It would be equally strange if radicle didn't mention git. They both wrap git.