Git does not give perfect integer revision numbers that increment on each commit. Instead, git hashes the commit data and uses that as a unique identifier of the commit. That means one commit could be
8d844d8d… and the next
f1728db4…, which is incomprehensible AND unusable as (part of) our version numbering convention.
However, git allows you to create descriptive labels for marking specific points in history as being important, i.e. creating pointers to specific commits. These pointers are called tags. Typically, tagging is used for marking release points (
v1.2.3, and so on), and that's exactly what we do, as well.