Emulator

The version is:

2407-7
Revision: 654ccb0b705c65acbb91d030e101b11e3da586d6

It was this way for a few weeks.

I've just updated manually - same on the last development one:

2407-37

Revision: bb03fc04ccbdd5a86dfbe7ab6179d240f5b0e076

While the manual opening of the Updater app works as expected, on the 2407-43 version the updating from Help -> Check for updates... still does nothing.
I wasn't able to test that with the test build from the https://github.com/dolphin-emu/dolphin/pull/12926 pull request because "Help -> Check for updates..." was not functional there (it won't even load the list with the differences)

If you open Console.app (Applications -> Utilities), enable streaming, type "Dolphin Updater" into the search box + press enter, and then try running Help -> Check for Updates, does anything appear in the console log?

"/Applications/.Dolphin Updater.2.app/Contents/MacOS/Dolphin Updater not valid: Error Domain=AppleMobileFileIntegrityError Code=-420 "The signature on the file is invalid" UserInfo={NSURL=file:///Applications/.Dolphin%20Updater.2.app/Contents/MacOS/Dolphin%20Updater, NSLocalizedDescription=The signature on the file is invalid}"

"AMFI: Check-fix enabled for binary '/Applications/.Dolphin Updater.2.app/Contents/MacOS/Dolphin Updater' with TeamID '97835T4369', identifier 'com.dolphinteam.dolphin-updater': broken signature treated as unsigned without privileges. This workaround will not work for software built on or after 10.12."

Thank you. I've been able to reproduce on one of my machines. I've opened bug 13567 for this problem.