dman command will automatically download a manual page to a temporary cache, and then show it. It's good for displaying manual pages for software that is not installed, though sometimes it doesn't work well, and you do have to wait for the manual page to download. (Manual pages are small though, so that doesn't usually take long.)
dman, install the bikeshed package.
dman's own man page notes:
Note that the network operations will be a little slower than
you are used to, when reading a manpage. Also note that you must be
internet-connected, and able to access manpages.ubuntu.com for this
utility to be useful. Finally, the algorithm that
dman uses to
retrieve remote pages is considerably simpler than that of man(1).
dman may appear to do nothing at all, if it's unable to find the manual page you're looking for (even sometimes when it should find it). And there's a small delay before and after manual pages are shown. But overall, it's a handy utility to have around, especially when you want to learn more about a program without installing it or switching to a web browser.