svnversion's man page contains: NAME svnversion - Produce a compact version number for a working copy. svnversion --help rightly puts "version number" in scare quotes: Produce a compact 'version number' for the working copy path WC_PATH. TRAIL_URL is the trailing portion of the URL used to determine if WC_PATH itself is switched (detection of switches within WC_PATH does not rely on TRAIL_URL). The version number is written to standard output. Indeed, the output may be a number, but it may contain more than a number (for example, "4123S"). It would be more exact to refer to a "version string".
Original issue reported by chealer