$ git clone -n https://src.fedoraproject.org/rpms/rust-xml-rs.git /var/lib/mock/f39-build-1445636-32653/root/chroot_tmpdir/scmroot/rust-xml-rs
Cloning into '/var/lib/mock/f39-build-1445636-32653/root/chroot_tmpdir/scmroot/rust-xml-rs'...
$ git fetch origin 34cc0a06413704d9b4c7c0e838d341c0e46e5967:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-xml-rs
 * [new ref]         34cc0a06413704d9b4c7c0e838d341c0e46e5967 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 34cc0a0 Update to version 0.8.19; Fixes RHBZ#2240310