If you've read manuals for, say, GNU Make, GNU Awk, GNU Libc or GCC online, you've read info documentation, even though you might not know what that is, and have never used the info program.
The GNU Awk man page is about 1600-something lines long; it doesn't compare to the manual.
The GNU Make man page renders to under 300 lines. Not the manual, obviously; you will learn next to nothing about GNU Make from that page.
If you install the GNU Make documentation, you can use "info make". I sometimes do that, but most of the time I go for the all-in-one-HTML-page online version. I mean, come on, you can just Ctrl-F search the whole page easily; it's a no brainer unless you need regex. Speaking of regex, the info pager searches are regex and you often need to backslash-escape characters when looking for code-related glyphs.
There is a way to read info pages all in one. Here is the trick, are you ready?
info <whatever> | less