Specific name for a collapsible bottom drawer menu?

I am looking for examples of this, because I eventually want to use it in a long scrolling Jupyter notebook - however, when I use "collapsible bottom drawer menu" in search, I mostly get hits for unrelated solutions for mobile (closest I got to was What are the little arrows called that hide additional details? )

So, here is more specifically what I'm looking for: I would like to have a "position: fixed" element on the bottom of the page (so it keeps it position, no matter where in the document we are, in terms of scroll position - and thus, it is on top of any other layout element), which would indicate that there is a menu to be opened - so the below shows its "collapsed" state:

Then when you click the button, the menu expands, and you can use whatever functions are there:

... and of course, in the end, you can also use the "arrow" button to "close" (i.e. "collapse") the menu as well.

Is there a specific name for this design pattern - and are there any decent HTML/CSS examples online, I could look at?