This is a helpful tip, but I feel like it kinda reinforces the broader point about emacs's lack of discoverability. I've been using it for years and wasn't aware of this feature until today.
This is how I've discovered most things outside of just reading the documentation (and usually I go to the documentation once I find it). It's also helpful that the info pages in emacs are also searchable with:
M-x info-apropos some-string
Both are kind of firehoses, but C-s inside the resulting buffer can usually narrow it down pretty quickly.
I'd like to know what other editors have a discovery system like this built-in.
