$ git clone -n https://src.fedoraproject.org/rpms/perl-Sereal-Decoder.git /var/lib/mock/f45-build-26233-616/root/chroot_tmpdir/scmroot/perl-Sereal-Decoder
Cloning into '/var/lib/mock/f45-build-26233-616/root/chroot_tmpdir/scmroot/perl-Sereal-Decoder'...
$ git fetch origin 4162982f7c58d00b4ac556165c6e04fbcf61b376:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Sereal-Decoder
 * [new ref]         4162982f7c58d00b4ac556165c6e04fbcf61b376 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4162982 Update to 5.010 (rhbz#2511545)