$ git clone -n https://src.fedoraproject.org/rpms/rust-cc.git /var/lib/mock/f40-build-2711232-71830/root/chroot_tmpdir/scmroot/rust-cc
Cloning into '/var/lib/mock/f40-build-2711232-71830/root/chroot_tmpdir/scmroot/rust-cc'...
$ git fetch origin eea5e6a116817bf34344468c35a0284191a7f36e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cc
 * [new ref]         eea5e6a116817bf34344468c35a0284191a7f36e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eea5e6a Update to version 1.0.90; Fixes RHBZ#2268347