The page doesn't say it, how well it handles very large files? Also, how does it handle editing files with various encodings? Asking this while having Notepad++ in mind.
I use Kate all the time and IME it doesn't. In fact it struggles even with relatively small files. In fact try this:
seq -f"foo %100.100f" 1 1000 > /tmp/test1000 && kate /tmp/test1000
...and watch Kate struggle with a ~100KB file. It seems to be related to the text layout or something along these lines (i.e. it isn't because of whatever data structure it uses for text, modern PCs should be able to handle the naivest of naive text editor structures even when editing a few MBs without sweat) because the slowness is triggered whenever text is about to be displayed (e.g. when scrolling) or lines are added/removed (modifying a single line is fine, but if you move say to the middle of the file, press Enter and keep it down you'll see that it struggles to add new lines).
I'm only using for editing text files and source code so it rarely bothers me personally but it can be annoying sometimes.
What do you consider as struggle? Here this works fast and flawless with Kate, VS Code, vim... Though, I did not use /tmp, but $HOME. But I doubt this would make a difference, unless your KDE is broken and Kate struggles because of kio on opening the file.
Choppy scrolling, taking up to a second to add a line in the middle of the text, etc. As i wrote, the issue was with scrolling and adding/removing lines - so most likely text layout stuff. The file I/O was fine.
Could it be then, that the layout or styling of JSON is performant, while the one for random text is not? But then again what's there actually to style or layout in random text.
