It is currently SQLITEVERSION-rAPSWREV. There are several problems:

• -r clashes with gentoo
• msi doesn't want any non-numeric parts
• setuptools doesn't like non-numeric parts, with carve outs for 'alpha', 'beta' etc but not -r
• the distutils included in setuptools has its own complaints
• setup.py tries to mangle the version number in places to meet the rules

This approach was originally taken because SQLite used variable version numbers - 3.8.11.1. Since 3.9 it has stuck to semver so we only need to worry about 3 parts, and can use a 4th part for the apsw revision.