They’re using a window manager over a full DE, so it’s likely the usual case of preferring minimalism to the very complete desktop environment (which many consider bloated). I’m a window manager person myself, but I’ve been giving KDE a good honest try for the past couple of weeks. It’s definitely very nice if you want the full DE experience.

Just tried with GPT-4, it said “Sure, here is the letter A 2048 times:” and then proceeded to type 5944 A’s