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.
I'd like to know what other editors have a discovery system like this built-in.