Localization doesn’t just mean string translations. Apple platforms give you the freedom to redo the UI to fit the language. For example, parts of System Preferences (not sure about Settings) would look completely different in languages with long words because the original design for English simply didn’t fit. The translators rearranged buttons to make the text fit.

Sure, but that's a few KBs for each locale at most. Still a long way to 100 MB.

They probably just have lots of leftover localized assets that nobody dares to touch as they aren't sure if it's used anywhere.

Thank you! I've been wondering about exactly this, your explanation makes complete sense.

I just looked. In this case, it is just string translations.

In the version I'm looking at there are 27,470 .strings files totaling 69 MiB, but they take up 155.9 MiB of disk space due to the 4 KiB filesystem block size.

The keys for the strings take up 39% of the space while the values take up 61%. About 12% of translations are duplicated (the word "Cancel" is translated like 53 times)

So 55% of the space used for strings localization is just pure waste due to having so many small files. The long keys are rather wasteful too and about 12% of the translations are duplicated (i.e. the word "Cancel" is translated 50+ times per language).

Honestly, it just looks like no one cared.

The version I'm looking at has 27,470 strings files, mostly of them less than 4 KB each.

Since the iOS filesystem uses 4 KB blocks, it looks like about half the space is just wasted.

It probably isn’t just text that is localized.

Any rtl language will probably require a lot of different assets. If for no other reason than gradients. Plus anything asymmetric.

images also may need localization.