I think that’s the one.
Maybe I’m getting a little too old; in fact in several apps I already used chevron.down and another one looking the same but with a different name I can’t recall just now.
A search for ellipsis in the SF Symbols app shows there is no ellipsis.circle with an arrowhead-down.
Therefore one may have to make its own, using a canvas (as I did) or by other means.
If you mean the one from App Wrapper 4, that’s actually a Popupmenu with a declare to make it into an Action Button and inserted it into the toolbar.
It uses NSImageNameActionButtonTemplate so it gets the correct icon on different OS versions as opposed to SF Symbols.
All the declares to do this and more are included as part of the Ohanaware App Kit
App Kit 2021 - Building Better Mac Applications
Yes, I noticed it in Activity Monitor, and now also in App Wrapper 4.
I thought it was actually a popupmenu with declare, but didn’t know which one.