Well, you can open any file with Notepad and copy paste a content to any other file ..
But usually that won't help, in most case. Yes, you can even copy entire picture's hex code to another and it kinda works... But usually that won't help.
ALL weidu mods use backup folders, as when you open the setup-*modname*.tp2, it starts from saying the backup folders location, with: BACKUP ~foldername~ into which it will make folders when installing the mod, and moves overwritten original files. The subfolders name is the component number featured in your weidu.log file's log.
Now, if the file has not been modified by other mods, it won't be found in the override folder ... meaning that when the backup is made, it won't be at the backup either, as the game actually packages the original game files in the large .bif files that the game can read faster than data that's in the override folder.
To get the original file from the .bif's to be the one the game uses, you just need to delete any file that the game has in the <gameinstall folder>/override/ -folder. I don't know what xp file you mean, I assume it's the one that features the bonus xp you get from disabling traps and unlocking door etc, it's called "xpbonus.2da". There's also the xpcap.2da and xplevel.2da files.
There, by the by, is no "XP fixer" mod, it's called something else, as you can't fix what isn't broken. And there are multiple xp tweak mod, but that's not what you mentioned in the first post.
Yep, Jarno Mikkola. my Mega Mod FAQ. Use of the BWS, and how to use it(scroll down that post a bit).
OK, desert dweller, welcome to the sanity, you are free to search for the limit, it's out there, we drew it in the sand. Ouh, actually it was still snow then.. but anyways.