Facebook is sending out new “Developer Alert: App Review requirement for pages_show_list” emails.

Yes, SNAP does use pages_show_list permission to show the list of pages in the dropdown “Where to post” selection.

The good news is you don’t need to do anything.  Facebook says that if you already approved for manage_pages, you don’t need a separate approval for pages_show_list

manage_pages is a main permission required for SNAP, so if you are already using SNAP, you already approved for it.