overriding errors.php translation file

[TurkeyFish]

PS 1.6

Where do I place the file translations/en/errors.php to override it, either in my theme or in the overrides folder? 

I'm getting a 404 error when trying to save edits to the Error Messages translation in the backoffice. That's another problem, but to avoid it, I'd like to manually copy and edit the file so that it won't get overwritten during my next PS upgrade.

Edited February 26, 2020 by TurkeyFish (see edit history)