$ git clone -n https://src.fedoraproject.org/rpms/rust-memmap2.git /var/lib/mock/f40-build-2642378-66450/root/chroot_tmpdir/scmroot/rust-memmap2
Cloning into '/var/lib/mock/f40-build-2642378-66450/root/chroot_tmpdir/scmroot/rust-memmap2'...
$ git fetch origin 2b55fab609844cd23e69c4b1aba9ad51da646974:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-memmap2
 * [new ref]         2b55fab609844cd23e69c4b1aba9ad51da646974 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2b55fab Update to version 0.9.4; Fixes RHBZ#2260317