This version-controlled branch (with UUID qhs03buett12xusmwmh94jghc) contains a list of the newest commits of most (optimally all) of my public repositories, for quick update checks without polling individual repositories.
The basic idea has been borrowed from the lists of available packages in many Linux distributions.
Instead of polling for updates from every version-controlled branch which has been checked-out locally, just poll THIS branch and update it if necessary.
Then you have a list of the latest commits, and can quickly determine which of your check-outs are still up-to-date and which ones are not.