How to exit from ":doc"?

I have started reading the page.
It contains “See :doc keys goto-commands” links.
But does not mention how to return from the doc page. (How to exit the help. How to quit the doc.)

After a day, I have a guess that maybe “doc” opens a (debug) buffer, and what one wants is to close (“delete”) this buffer (with “:db”). Or, alternatively, switch to other buffer (with “:bn”, “:bp” or something).
Are these the proper commands? (Or are there simpler (1-keystroke) which I missed?)

Kakoune opens the doc page in a scratch buffer (buffer without a file backing store).

So it is totally appropriate to use the buffer commands (:db etc.).

Since “delete buffer” is so common for me, I have mapped it to a convenient key (<space-d>).

Are these the proper commands?