An optimization pass on the game would be an extremely welcome sight

[Shadow_rainbow]

Wow, 800+MB XML files to parse! Notepad++ has trouble just trying to scroll that volume of text any notable distance (like, it seems to hang up for a couple of minutes).

https://www.sublimetext.com/
Much better at handling large files than Notepad++

I'm amazed at the difference here. Not that Sublime isn't sluggish when working with this monster -- it is, and doing something like folding/unfolding, especially for large amount of instances, takes minutes -- but at least it allows for normal scrolling through it and somewhat normal operation with the document.
Thanks for the advice, this utility might come in handy sometime.

[alt3rn1ty]

Yep its a good open source editor. When decompressed my X4 Game saves are around 845mb, and even Sublimetext has trouble with it. But for most text editing Sublimetext is very much a better option, one of the authors original design goals was large file handling better than any other at the time.
If you ever need to do side by side diff of files, watch the video on the home page for a quick clue on how to, its a bit different to say notepad++ plugin which used to do the same.

The native diff feature requires the files to be part of the same project or folder. To use it, open the folder containing the files via File > Open Folder... or Project > Add Folder to Project. Ensure the Side Bar is visible (View > Side Bar > Show Side Bar). Select the two files in the Side Bar by holding Ctrl (Windows/Linux) or ⌘ (macOS) and clicking each file. Right-click on one of the selected files and choose Diff Files... from the context menu. This will open a new tab displaying the differences, with changes highlighted in red and green.

Alternatively, you can compare two open files directly by selecting both tabs (using Ctrl or ⌘ to select multiple tabs) and then right-clicking on one of them to choose Diff Selected Tabs....
This method works in Sublime Text 4.