The manual has fallen into disrepair. It’s a disgrace. Parts of it are missing, parts of it remain incomplete, some terms are out of date & don’t match what you see in Blender, and there’s no clear way to report the errors or offer corrections. The built-in link to documentation sometimes leads to a blank result.
Today I found this thread because I hoped to find some help, because searching the word “Hair” in the online manual turns up … nothing.
That’s right, no results for “Hair” in the Blender Reference Manual. That’s absurd. No results for “fur.” 2 results for “particle.”