in my case as shown in the screen shot nothing happens. No login window to login to Google appears as it should.
you can see from the screen shots as I have put safari next to darktable and taken the first screenshot and the second shot is after I click the login button, only the enter verification dialogue box appears No change in Safari.
I am here on Windows 10 and dt 3.0.0rc1. Trying to export to google photos and authorize a new account opens a chrome window as expected, but when i select my account i get the following error message:
I have an installtion on W10 too and the google export works well.
Once the exclamation mark shows up one can use the left side button to open the darktable / goolge connection in an “unsafe” mode. Once done everything works as designed.