[djao]

Neither gnome-terminal nor bash link against readline. I'm pretty sure they just copied the feature; it's not that they use readline in any way.

There's lots of other programs that use C-q for quoting, for example emacs, and readline probably copied it from there in the first place.

When pasting text, it's a different code path than quoting. The terminal surely knows when text is being pasted. If nothing else, a simple heuristic based on typing speed is enough to tell apart typing and pasting.

[lmz]

I investigated some more and this is called "bracketed paste" and both the program and terminal must support it (program must enable it). https://invisible-island.net/xterm/xterm-paste64.html