Apart from the online manpage archives, there’s man -k and grepping the manpage directories, but that’s not really ideal (although that’s what I did when I started Unix a long time ago).
There are help browsers like in kde which are kind of nice but I’m not sure if they do a full text search. But they’re nice for info pages.
RobotZap10000@feddit.nl 1 week ago
Would explainshell.com suffice?