Does this tell you?
You were not able to disable it due to file permissions? (That doesnât sound like expected behaviour.)
Yes. At the bottom there, the System have read/write, but Users only have read. And SketchUp is running with the current userâs permission. That explains why you cannot uninstall.
Presumably the extension is installed via a separate installer?
Affirmative.
I should clarify. The memory leak happens for me even if the navigator is not attached to my macBook. When traveling without the navigator, that was a real pain before I stumbled on the workaround of closing the default model window. Using the EM to turn it off and on was hit or miss because the leak would take off before I could even get the EM open. So I wrote a little script to toggle the extension between .rb and .rb! without running SketchUp, and that required write permission for the folder. Not knowing how the EM manages enable/disable, I thought it might be relevant, but from what you say I guess not.
As @simoncbevans noted, their installer runs outside SketchUp and the EM. macOS requests an admin password to allow the install, which is why they can write to that folder.