I’m pretty sure they’re not, but in the 5.1.6 AIO, there are still 4 for en_GB, and 3 more for nl, next to our own gramps.mo.
And this suggests that the old AIO installer (or its auhor) was aware of the dependencies, in some way. And technically, the situation is that some DLL’s that we include have dependencies, that must be included, and this new AIO is a bit too radical, in the sense that it doesn’t include any, or all, with your latest change, and neither is good.
I had quite a busy week, but I may have more time this weekend, so I may be able to help, by looking at the code of the old AIO, if I can find that. And I hope that this can also tell me why the new 5.2 doesn’t detect the UI language in Windows, 10 or 11, and works well in Wine.
There is another approach, and that’s a program that was once distributed by Microsoft, with the Windows SDK that I used in the early nineties, and that’s called dependency walker. It’s still available, and it may help if we can’t find more clues in the old AIO.
It’s been a while since I used it, and I have no idea whether it actually lists dependencies on MO files, but it might be worth a try.