Have reviewed 16 year old code for a very well known company in the last week with this exact comment peppered throughout, alongside delightfully helpful comments like:

// do not delete or change this it just works

// TODO temporary fix added 12/09/11 to fix incident must be removed ASAP

// CAUTION this returns false here instead of true like it normally does, not sure why

// if true then matched to valid account not is true

A friend of mine moved to Japan about 10 years ago and has spent a lot of time solo developing his site, Kanpeki Study, for efficiently learning Japanese kanji and vocabulary in bitesize, daily chunks. I’d be doing all his effort a massive disservice if I didn’t mention it - hopefully turns out to be a good fit for you 😄.