$ git clone -n https://src.fedoraproject.org/rpms/perl-Authen-U2F-Tester.git /var/lib/mock/f45-build-21802-588/root/chroot_tmpdir/scmroot/perl-Authen-U2F-Tester
Cloning into '/var/lib/mock/f45-build-21802-588/root/chroot_tmpdir/scmroot/perl-Authen-U2F-Tester'...
$ git fetch origin 841f108a64d79d931a979b2f6f8e84f67c9da1c4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Authen-U2F-Tester
 * [new ref]         841f108a64d79d931a979b2f6f8e84f67c9da1c4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 841f108 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild