If you think it's mostly unfamiliarity, then that's a great opportunity to suggest some time spent to document that code (and/or operations thru that code). It

If you think it's mostly unfamiliarity, then that's a great opportunity to suggest some time spent to document that code (and/or operations thru that code). It helps w/ the understanding, and should be a precursor to figuring out if a redesign could help that "tech debt".