These files are snapshots of the Ur-Quan masters Git tree excluding the content.
They are automatically made every 4 hours if there are any changes in Git.
The newest snapshot is always on the top.

If you want to use one of the binaries, you should already have The Ur-Quan Masters installed. You will need to replace your existing uqm.exe or uqm-debug.exe with one you download here.

The content update .zip file needs to be put in the content/packages/ directory inside the directory where you installed The Ur-Quan Masters. You should not unzip it, and you should leave the content file(s) of the last release in place.

These snapshots are made from the Git tree where we do our development, which is where bugs like to hang out. If you need stability, you might want to wait for an official release.
If you report a bug you find in these snapshots, please make it clear that you found it in a Git snapshot.