(sorry for not using an issue template, but I failed to fit it in)

Applied Energistic 2 has a guide book which contains awesome visualizations for AE2 concepts and tutorials. However, it would be nicer if it could be localized more easily without the following issues.
Those are:

No localization support

Currently the guide book asset loading procedure doesn't respect language options, meaning that the mod itself cannot be embedded with multiple language versions of the guide book.
Admittedly, one could distribute a Resource Pack that contains an localized variant of the guide book, and use it to override the default English guide book. (We actually are doing this at CFPAOrg/Minecraft-Mod-Language-Package for Chinese, which is basically a hopefully universal resource pack that contains translated assets for many mods.) Well, if only we could do so without the following issues.

Little-to-no compatibility between versions

It is not uncommon to have translation files *desync'ed8 from source files, especially when the translation is not centered in the mod repository. It would have been fine, except that in this case, the AE2 guide is rather sensitive to version changes, and may corrupt the guide book (or even possibly crash the game if I remembered correctly) if some particular discrepancy exist. So it would be totally fine if we we can play the game with slightly out-to-date translated guide books, but not if the guide book corrupts every update.

Weird behaviors for extra contents

It's not uncommon for other mods (esp. add-ons of AE2) to add content to the AE2 guidebook, and we attempted to pack those contents into one resource pack for easier distribution. However, from the user reports it seems that such distribution causes unexpected outcomes, like showing up contents in add-ons when they're not present, or outright crashing the game. I haven't really invested into this problem (or if it can be fixed within the current infrastructure), but this just seems weird to my eyes.

Well, I'd say these problems are frustrating for localizers, and especially for the project I'm working on. We literally had a complete, vetted translation of the AE2 guide book and some add-ons, and had to take these down after we actually distributed them. Yes, we could forget about distributing a universal pack and just decide to publish these translations as independeng and versioned subpacks, but it would be way better to try to get it fixed from this side.

We can't provide first party guidebook translations because we just don't have any people capable of doing translating it, and even less so for keeping the translations up to date.

With that said, I think it would be nice if the guidebook could support switching languages, even if they are only provided by third parties (e.g. by loading it from path/to/page-laguagecode.md) (tho imo it should be a separate toggle, and not necessarily be the same as the game language, so people can still access the english version without having to change their language everywhere, to a "same as game language" setting might also be nice)

For the issue with crashes: it would be nice if you could report those, so they can all get fixed.
imo, a version mismatch in guide pages should at most lead to pages or parts of pages not being rendered, but not to crashes (tho crashing has the advantage that people usually notice quicker if something is broken, and are more likely to report issues in my experience)

for addons, It might be possible to use pack overlays to only activate parts of the pack if addons are present

Well, I actually don't expect built-in translations (although it would be nice), for just the reasons you listed. It's way harder to maintain than those language files.

As for switches for languages, that's definitely beneficial for localizations. A I personally don't need a switch separate from the language switch of the game, but it's probably fine to have.

About the crashes, well, I might have misread the reports. I'd say it's probably that the resourcepack get unloaded entirely if an error occur (if pages mismatch). A bug report will probably be sent, although maybe not by me, as I'm currently away from my computer and can't really test these.

I wonder how to switch pack overlays on depending on mods installed though. From Minecraft Wiki I could only see a way to switch it depending on pack version. Is it a feature added in mod loaders or what?

https://pastebin.com/5cJLuy2x
Captured the part that threw the exception.

latest.log
The full latest.log. Error occurred in line 1123.