Wow, after 25 years of Unix experience, I learned that you can filter output in #less.

Press ampersand (&) and enter a regex to show only lines matching the regex.

Press ampersand (&) and then exclamation mark (!) to apply an inverse filter.

@_xhr_ TIL!

BTW, another neat function (at least in the GNU version?) is pressing Shift-F to make it follow the file (scroll to the end and update when the file changes) - useful for logs!

@Doomed_Daniel @_xhr_ this is incredibly useful