You could also try to check the version of the backup file like so:
root@cmkserver:~# tar -t -v --wildcards -f backup.tar.gz "*/version"
lrwxrwxrwx stest/stest 0 2020-06-18 15:54 stest/version -> ../../versions/1.6.0p12.cee.demo
-rw-r--r-- stest/stest 18 2020-06-09 16:30 stest/.version_meta/version
lrwxrwxrwx stest/stest 0 2020-06-18 15:54 stest/version -> ../../versions/1.6.0p12.cee.demo
With that output I know that backup.tar.gz contains a backup of the site stest which was running with 1.6.0p12.cee.demo. Maybe that helps.