$ git clone -n https://src.fedoraproject.org/rpms/rust-escape_string.git /var/lib/mock/f41-build-side-1-2940097-35324/root/chroot_tmpdir/scmroot/rust-escape_string
Cloning into '/var/lib/mock/f41-build-side-1-2940097-35324/root/chroot_tmpdir/scmroot/rust-escape_string'...
$ git fetch origin 16af65e30cd9833a3d993955533801cb9b4aba59:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-escape_string
 * [new ref]         16af65e30cd9833a3d993955533801cb9b4aba59 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 16af65e no longer needed