notifications – What is the official name and nature of the panels that are sliding upwards in web browsers

bit of a newbie question maybe. I think the title sums up pretty good what I am asking but, here is a screen capture of the particular type of in-browser panels I’m wondering about

enter image description here

I don’t mean the ones android system shows when there is no default app setup. I mean, in the browser itself. I don’t imagine they are the same are they ?

I’ve seen the Android dev documentation about “SlidingPaneLayout” which sounds similar. Except, the one I’m interested in is not “dismissable” or “resizable”. It actually takes over the flow and darkens the background until the user either selects an option it offers or, swipe kill the browser tab.

Are those part of the webwiew? I’m wondering what term I need to look for in order to get the details about those panels.

Or, if I am wrong in anyway here, maybe someone could just give me a brief explanation? would be much appreciated

Search results on google mostly brought rants about a completely different type of browser notification so I figured i’d try asking here.

Anyways, thank you for reading