$ git clone -n https://src.fedoraproject.org/rpms/rust-backtrace.git /var/lib/mock/f41-build-side-1-2934423-35233/root/chroot_tmpdir/scmroot/rust-backtrace
Cloning into '/var/lib/mock/f41-build-side-1-2934423-35233/root/chroot_tmpdir/scmroot/rust-backtrace'...
$ git fetch origin e0edd9d304e4cdcfe4163df05a8a03862ff8e78b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-backtrace
 * [new ref]         e0edd9d304e4cdcfe4163df05a8a03862ff8e78b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e0edd9d Update to version 0.3.74; Fixes RHBZ#2310767