$ git clone -n https://src.fedoraproject.org/rpms/rust-fastrand1.git /var/lib/mock/f38-build-side-43-rust-devel-1414582-31449/root/chroot_tmpdir/scmroot/rust-fastrand1
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1414582-31449/root/chroot_tmpdir/scmroot/rust-fastrand1'...
$ git fetch origin af1f92f943b5f3ce155362bcac346a26e34ee55b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-fastrand1
 * [new ref]         af1f92f943b5f3ce155362bcac346a26e34ee55b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at af1f92f Initial import (fastrand 1 compat package)