I've tested [nonprism-testing/geoclue] (locally built).
As of writing this, my system is up to date:

$ sudo pacman -Syu
...
warning: geoclue: local (2.5.5+6+gea52170-1.nonprism1) is newer than extra (2.5.5+6+gea52170-1)
...

For the first test, [nonprism] was enabled. However, [nonprism/your-privacy] was not installed.
The last test was by having [nonprism-testing/geoclue] installed and masked geoclue.service as proposed on StackExchange .

All tests were performed with an active internet connection and without Tor, VPN, ...

In short: [nonprism-testing/geoclue] does not prevent geolocalization. Masking geoclue.service is needed and seems to prevent geolocalization.

• gnome-weather
  • [nonprism/gnome-weather]
    Does not start:
    

    $ gnome-weather
    § journalctl /usr/bin/gnome-weather
    -- Reboot --
    Dec 18 18:36:09 host org.gnome.Weath[4349]: JS WARNING: [resource:///org/gnome/Weather/Application/js/app/world.js 73]: reference to undefined property "autoLocation" 
    Dec 18 18:36:09 host org.gnome.Weath[4349]: JS ERROR: TypeError: CurrentLocationController.AutoLocation is undefined
                                                          _init@resource:///org/gnome/Weather/Application/js/app/world.js:73:1
                                                          wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
                                                          _init@resource:///org/gnome/Weather/Application/js/app/window.js:65:27
                                                          wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
                                                          _createWindow@resource:///org/gnome/Weather/Application/js/app/main.js:159:16
                                                          wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
                                                          vfunc_activate@resource:///org/gnome/Weather/Application/js/app/main.js:191:19
                                                          wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
                                                          main@resource:///org/gnome/Weather/Application/js/app/main.js:207:13
                                                          run@resource:///org/gnome/gjs/modules/package.js:222:12
                                                          @/usr/share/org.gnome.Weather/org.gnome.Weather.Application:6:1
    
    

  • [extra/gnome-wheather]
    was able to determine my location.
  • [extra/gnome-weather] with masked geoclue.service
    was not able to determine my location.
    Output:
    

    $ gnome-weather
    Gjs-Message: 19:25:22.541: JS LOG: Failed to connect to GeoClue2 service: Error calling StartServiceByName for org.freedesktop.GeoClue2: Unit geoclue.service is masked.
    

• empathy
  I've never used the application before.
  The output in the terminal was:
  

  $ empathy
  (empathy:6103): tp-glib-CRITICAL **: 18:40:22.723: tp_protocol_get_param: assertion 'TP_IS_PROTOCOL (self)' failed
  ...
  

  
  Furhtermore I was not able to add accounts and thus use the app in a meaningfull way. Please ask for screenshots if necessary.

• gnome-maps
  • [nonprism/gnome-maps]
    The app runs fine and the button for "Go to current location" was greyed out.
  • [extra/gnome-maps]
    Detects localization after a short time.
  • [extra/gnome-maps] with masked geoclue.service
    Clicking on the localization button results in a message "Failed to connect to localization service" and my location seems not to be found.
• gnome-settings-dameon
  I don't know how to test whether it has any clues about the location. However gnome-shell runs fine.

• redshift
  • [nonprism/redshift]
    

    $ redshift
    Trying location provider `geoclue2'...
    Using provider `geoclue2'.
    Using method `randr'.
    Waiting for initial location to become available...
    

    
    The program does not seem to make any progress.
    Running with the hardcoded location
    

    $ redshift -l XX.XX:YY.YY
    

    
    is fine.
    All in all, redshift behaves as expected.
  • [extra/redshift]
    

    § redshift
    Trying location provider `geoclue2'...
    Using provider `geoclue2'.
    Using method `randr'.
    Waiting for initial location to become available...
    Location: XX.XX N, Y.YY E
    

    
    The returned location is in the city I am. geoclue must have returned the location.
  • [extra/redshift] with masked geoclue.service
    Same as in case [nonprism/geoclue].

• webkit2gtk
  I don't know, how to test this.

Please let me know if you need any further information.