alt Hacker NewsThey mean pretty much like they say.
readline is a thing that reads lines being input by a user, in a terminal context. It includes a number of keybindings that make editing & navigation while editing the line-to-be-input easy, such as ^A, which moves the cursor to the start of the line.
bash or zsh in emacs mode is similar, those these two have their own line editors, technically.
macOS adopted some (but not all) of the common keybinds from that era into their UI. I.e., in a GUI text entry field in macOS, you can hit ^A to move the cursor to the start of the text entry.
(I don't know that this particular UI-ism would make or break an OS for me, personally, though.)
Given how UI is implemented, this would be up to the toolkit. In GTK3, this was called "key themes"; there was, I think, an "Emacs" theme that would do what they desire. I do not know if GTK4 still has this, however (and I suspect it was removed).
(I think more users are going to expect ^A to be select-all, and home/end and ^← for word navigation, etc. These are the defaults. Thus key themes were probably little used.)
Okay, I understand now.
And that's just a wildly nitpicky criticism by the person that brought this up.
To me, as long as the OS includes the functionality, the way it's presented to the user, how customizable it is, and what keys they use is generally irrelevant. Each user of each OS will be used to whatever that OS chooses to set up.