I've been working on and off on another significant update. Sifting through old patch notes and scouring even more vanilla files, I found things going back years and even more terms documented nowhere. I've also cleaned up the old keyword lists for outdated terms and added functional highlighting for title and event_target scopes, though these may interfere here and there. They can be easily disabled, as per updated instructions contained in the download archive.
In addition, I've added two new highlighting languages for Graphics (.gui and .gfx) and Localisation (.csv and .txt for customizable localisation). They work similarly to the old ones.
Finally, I've updated installation and update instructions, for use with current, and hopefully future, Notepad++ versions. Detailed instructions inside the archive.
Please let me know if I've missed anything, or if you have constructive feedback!
Great work, but you didn't write it in the README that CK2lang.xml, CK2gui.xml and CK2loc.xml should go into "AppData/Roaming/Notepad++/userDefineLangs", not into "ProgramFiles/Notepad++/userDefineLangs" (which does not exist, I tried to create it and place the stuff there). It took some time to figure out the problem.
I bet others were confused too, so please correct it in the next update.
But thanks for this anyway!