$ git clone -n https://src.fedoraproject.org/rpms/perl-DateTime.git /var/lib/mock/f42-build-side-1-3499063-45964/root/chroot_tmpdir/scmroot/perl-DateTime
Cloning into '/var/lib/mock/f42-build-side-1-3499063-45964/root/chroot_tmpdir/scmroot/perl-DateTime'...
$ git fetch origin a14da4c645e86aa6695018a6b46e5c5ade200cce:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-DateTime
 * [new ref]         a14da4c645e86aa6695018a6b46e5c5ade200cce -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a14da4c Update to 1.66 (rhbz#2346459)