$ git clone -n https://src.fedoraproject.org/rpms/rust-tempfile.git /var/lib/mock/f40-build-2521232-61798/root/chroot_tmpdir/scmroot/rust-tempfile
Cloning into '/var/lib/mock/f40-build-2521232-61798/root/chroot_tmpdir/scmroot/rust-tempfile'...
$ git fetch origin 26ece708d588fe56b9648770bb6b742e88d01358:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tempfile
 * [new ref]         26ece708d588fe56b9648770bb6b742e88d01358 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 26ece70 Update to version 3.10.1; Fixes RHBZ#2266194