Not sure if this is a big or not, but I can’t find the sprite masking extension anywhere. I tried searching for it, and nothing showed up. Is it bugged, or was it deleted?
Also, yes, I had the experimental switch toggled
It might be because in the meantime, it got renamed from sprite masking to object masking 
Searching for sprite masking would likely not yield any results anymore
Alright, I searched “Object” in the prompt, and there it was, my bad.
Although, last night I tried to search “Mask” or “Masking” and it didn’t show up. Is that tag missing?
Nope, as shown in my screenshot it is working okay with mask.