That is about showing 'Open tabs' as a suggestion in the address bar drop-down list.

The location bar drop-down list can show history items, bookmarked pages, pages opened in tabs, top sites, and search suggestions. You can set what suggestions show when you enter an URL in the location/address bar bar.

• Settings -> Privacy & Security
  Address Bar: When using the location bar, suggest:
  Browsing history
  Bookmarks
  Open tabs
  Shortcuts
  Search engines

Thanks. I looked at what you suggested and mine is already set that way. I note a 'problem.' It appears to me that for, say, a URL that begins with a domain name of bbb.com, if you have an open tab from that site, obviously, it starts with 'bbb.com,' it will show the open tab as a suggestion. But if a site page has a URL of, say, app.bbb.com and you type 'bbb,' it will not show it as an open tab; if you type 'app,' it will show it. I am surmising that you have to know the first few letters of the actual URL.