Say how to just get error messages in the manual

‘-q’
‘--quiet’
     Turn off Wget's output.

‘-nv’
‘--no-verbose’
     Turn off verbose without being completely quiet (use ‘-q’ for
     that), which means that error messages and basic information still
     get printed.

So there is no way to just get error messages.

Wait. Google says:

"To display only error messages from wget and suppress all other output,
including progress indicators and successful download messages, use the
-nv (no verbose) option in conjunction with redirection of standard
output to /dev/null."

I see. Well please mention that in the manual.