When Google+ 7.0 rolled around last week, the major change that everyone spotted was the auto-hiding bottom tab bar. However, upon inspecting the apk, our resident teardown master Cody noticed a couple of strings that alluded to the addition of Custom Tabs. The feature didn't appear to be live back then so he scratched it off at something that was still being implemented.
<string name="custom_tabs_pref_summary">Enable Custom Tabs</string>
<string name="custom_tabs_pref_title">Open web links within G+ app</string>
However, it seems that feature has started going live for some users, likely through a server-side change. This means that whenever you click on any link inside the Google+ app, instead of being redirected to Chrome or any third-party browser that you use, the link will load inside a custom tab (if you have Chrome v45 and above, which by now almost everyone does). Custom tabs are faster to load than the full Chrome browser and lighter, but they keep your Chrome logins, autofill information, and they are as secure as Chrome is. They sound great, but the disadvantage is that you can't open a link and go back to reading your Google+ feed to see other pages, you'll have to exit the page first.
Google+ Custom Tabs aren't live for us yet, so the image used on top of the article is of a custom tab loaded from another app. By comparison, the Google+ custom tab should also show a Share button next to the overflow menu on top.