$ git clone -n https://src.fedoraproject.org/rpms/fedora-dockerfiles.git /var/lib/mock/f29-build-6297-1536/root/thebuilddir/tmp/scmroot/fedora-dockerfiles
Cloning into '/var/lib/mock/f29-build-6297-1536/root/thebuilddir/tmp/scmroot/fedora-dockerfiles'...
$ git reset --hard b1b1940df5660c725379878a1370142a78758f05
HEAD is now at b1b1940 - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild