Facebook video opening a web page?? How they do that

Hello everyone,

I am unsure if this behaviour is legal or not in terms of google adsense/facebook policies..

But can you guys please take a look at that facebook page (facebook.com/govirall) use your smartphone to access the page and click on any of their videos.. You will see a webpage opening under the video and the video is autoplaying.. and we can see google ads there.. How do they do that?!

Thanks,

with "watch more" button (feature is avaible only in fb ads these days)
from what i know if you put yourdomain.com on watch more button, that website will open in bottom half of screen , when people will watch video
you can try with one old video post from a page you own
(i made a test in the past, but i am not sure if video still works, i am not mobile right now)
try my link with smartphone

I tested but nothing special with other pages, can you take a screenshot?