Per discussion at https://gerrit.wikimedia.org/r/#/c/mediawiki/extensions/WikimediaMaintenance/+/582902/ it may make sense to remove the cleanupMl script:
I wonder if we can drop this whole script completely. It probably has been created before Ml normalizations were added into MW core, and I don't think it will be run ever again, but it's too old to get a complete history. I think let's just drop it?