Suppose I mount, under /path, some kind of distributed filesystem whose storage is replicated among many servers (for fault tolerance, availability, and performance) and then store a git repo into /path/to/repo.git.
If I clone from this, so that my origin is "file:///path/to/repo.git", is that then a decentralized git remote?
The `dgit://` protocol that gets registered with the `git-remote-dgit` helper is not in itself a remote resource, but rather a deterministic identity that has been registered with the Tupelo DLT (zonotope provided good details on this below). Therefore the ownership as well as the current state (branches, tags, maybe PRs in the future :), etc) of the remote repo is decentralized away from a single entity (aka GitHub/GitLab) - as the owner, you fully control it, nobody else can modify it - not even the dgit team.
The storage part of your dgit remote is much more on the "distributed" side. We chose sia's skynet because we think it's a great fit for this. However, the actual objects of the repo could be stored anywhere, S3, IPFS, exchanged over bittorrent, or even your local raspberry pi. Regardless of where the git objects live, there still remains a single, trusted, distributed index of your repository on the Tupelo DLT.
For Sia/Skynet, the Sia network is doing the hosting, meaning the file has high uptime even if the uploader does not, and even if nobody else chooses to pin/seed the file.