$ git clone -n https://src.fedoraproject.org/rpms/rust-serde_fmt.git /var/lib/mock/f41-build-side-1-3134919-39764/root/chroot_tmpdir/scmroot/rust-serde_fmt
Cloning into '/var/lib/mock/f41-build-side-1-3134919-39764/root/chroot_tmpdir/scmroot/rust-serde_fmt'...
$ git fetch origin e42aee5552fb0fa87033f26c7f225b8cb36baecd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serde_fmt
 * [new ref]         e42aee5552fb0fa87033f26c7f225b8cb36baecd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e42aee5 no longer needed