$ git clone -n https://src.fedoraproject.org/rpms/perl-AnyEvent-XSPromises.git /var/lib/mock/f45-build-21674-587/root/chroot_tmpdir/scmroot/perl-AnyEvent-XSPromises
Cloning into '/var/lib/mock/f45-build-21674-587/root/chroot_tmpdir/scmroot/perl-AnyEvent-XSPromises'...
$ git fetch origin b2397f2278f687c75baf7714a8c8e6066f3b93b1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-AnyEvent-XSPromises
 * [new ref]         b2397f2278f687c75baf7714a8c8e6066f3b93b1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b2397f2 Perl 5.44 rebuild