$ git clone -n https://src.fedoraproject.org/rpms/roc-toolkit.git /var/lib/mock/f39-build-1983027-43346/root/chroot_tmpdir/scmroot/roc-toolkit
Cloning into '/var/lib/mock/f39-build-1983027-43346/root/chroot_tmpdir/scmroot/roc-toolkit'...
$ git fetch origin 5459e50d39b3d805ebd07a5986b821e28579b7af:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/roc-toolkit
 * [new ref]         5459e50d39b3d805ebd07a5986b821e28579b7af -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5459e50 Fixed FTBFS