Invoking manually doesn't work either, so I think there's something broken about the default install of Zsh on macOS (though I *also* have it installed via homebrew). $ info --index-search=read zsh no index entries found for `read'
I had this problem on Linux Mint but not on Cygwin so assumed I'd
but actually I needed
sudo apt-get install zsh-doc now following works info --index-search=read zsh zzapper