TerabyteQbt/meta master branch:
What is this? This repository is a QBT manifest repository. QBT is an open-source dependency management and repostiory stiching tool. Think of QBT as being similar to the android development tool "repo", or git with submodules, but with many additional features and benefits.
This repository, "meta", is the repository where the metadata for qbt development is stored. You can think of this as the parent or root repo in the constellation of repos (including many satelite repos) that are used to build QBT. This is the repository where github issues, pull requests, and everything else relating to QBT development happens. Because of how QBT works, most of the actual code lives elsewhere, but all workflows start here.
QBT works by having an external metadata file in a separate metadata repository (usually called "meta") which refers to specific commits by sha1 in each code repository ("satelites"). If you want to inspect the code, or build it, you need to find the metadata repository (which if you are reading this, you have already done) and clone it, then run QBT. Usually, but not always, sattelite repositories are located next to the metadata repository on the server.
To enable easier code-browsing, some qbt developers also push satelite branches to github, but you should think of these repos as read-only. One example is the qbt repo here. Notice that because this is just a satelite repo, it has no README and the value of HEAD is not authoritative. To interact with this code in any way, you should use qbt and the meta repo.
For reproducibility, the version specified in the metadata must be authoritative, but branches can be changed on the server and cannot themselves be versioned, so instead QBT uses a concept called "pins". The code in the satelite is pushed ("pinned") to refs/qbt-pins/X where X is the sha1 of the commit. Because the branch itself is content-addressed, it can always be found (and should never be deleted, just like git objects). Because pins function like entries in a content-addressible database, they can be pushed in any order and at any time, as long as it preceeds the update to the meta repo which references them, which is atomic.
If you need to manually inspect the code, you can see the branches in the sattelite repositories using ls-remote:
git ls-remote <clone URL>
By examining the manifest file, you could manaully do what QBT does and stitch together a collection of clones with the appropriate sha1 checked out. It's all very transparent. Perhaps some day someone will write a bootstrapping script to do exactly this so people can build QBT without QBT.
The best way to view the code is to use QBT. For details, see The Qbt Website.
QBT is released under The Unlicense. The license file is here.
Some code built by QBT, or upon which QBT depends, may be released under other licenses, so check the satelite repositories and packages themselves for license information.