imo translation notes like the 27th tl/n should be included in the page, in the margin between panels. Because when it is about something added (or removed) in process of translations that might end up being a plot hole later, it is important to make it clear for everyone that it was not actually said in case author decides to run with a "misunderstanding plot" later on. Not just for people bothering to read a credits page, and even there there is value in having the note tied directly to the scene for instant gratification/relevancy.