$ git clone -n https://src.fedoraproject.org/rpms/rust-dummy.git /var/lib/mock/f38-build-side-43-rust-devel-1398535-31104/root/chroot_tmpdir/scmroot/rust-dummy
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1398535-31104/root/chroot_tmpdir/scmroot/rust-dummy'...
$ git fetch origin 34354c9ca3ef0cb45916c547af081ffca8a6825f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-dummy
 * [new ref]         34354c9ca3ef0cb45916c547af081ffca8a6825f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 34354c9 Update to version 0.6.0; Fixes RHBZ#2192960