$ git clone -n https://src.fedoraproject.org/rpms/perl-Test-File.git /var/lib/mock/f39-build-1439571-32268/root/chroot_tmpdir/scmroot/perl-Test-File
Cloning into '/var/lib/mock/f39-build-1439571-32268/root/chroot_tmpdir/scmroot/perl-Test-File'...
$ git fetch origin 0a9b5a33d7dd75efcb54ea40ddff1705890fdce9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Test-File
 * [new ref]         0a9b5a33d7dd75efcb54ea40ddff1705890fdce9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0a9b5a3 Fix FTBFS in Rawhide (rhbz#2229872)