There are two ways to see all the publicly shared pages:
From the channel overview
You can do it in the channel overview section, via clicking the 'Public' button at the top bar (see screenshot). You will be shown all public pages inside the channel.
From the search field
Another way is to do it from the search box. There you'll see the 'Public' button, letting you know what pages are public in the chosen channels (see screenshot).
