It doesn't work for GUI software though. And even for CLI tools mans are not universally used. Sometimes it's just --help and for more information one have to r

It doesn't work for GUI software though. And even for CLI tools mans are not universally used. Sometimes it's just --help and for more information one have to refer to a website (typically a README on github). It seems to me that that quality and quantity of documentation and help files for GUI software degrades over time. Probably because it changes so fast that documenting it would be too expensive. On other hand now we have a lot of software for free, and even paid one is less expensive than it used to be so it is unfair to complain about lack of documentation. But I miss high quality docs and built-in help I used to see until 2000s (may be even 2010s).