$ git clone -n https://src.fedoraproject.org/rpms/perl-Authen-U2F-Tester.git /var/lib/mock/f39-build-1643504-40237/root/chroot_tmpdir/scmroot/perl-Authen-U2F-Tester
Cloning into '/var/lib/mock/f39-build-1643504-40237/root/chroot_tmpdir/scmroot/perl-Authen-U2F-Tester'...
$ git fetch origin 9bd271ab706812f766668442c7b5d0c2510adc1a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Authen-U2F-Tester
 * [new ref]         9bd271ab706812f766668442c7b5d0c2510adc1a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9bd271a Initial import