I use Ubuntu Mate 20.04. When I use websites like maps.google.com, they won't get my location. It seems Ubuntu Mate has no location service enabled out of the box. On regular Gnome Ubuntu, it seems to be a part of their menu settings, but in Mate, I don't see any such options. I have searched the web a lot, but didn't find any info. It seems no one has ever asked this before. Which makes me wonder if the question is really that unusual.
Oh , and I'm connected via LAN. Maybe it matters, but I don't know. No Wi-Fi, just LAN.
Do you have geoclue-2.0 installed? Do you have your time zone set to the correct timezone? Do you have your proper latitude and longitude set under your on your task bar clock: calendar> preferences>location>add?
Now after you mentioned it, I installed geoclue-2.0. But the browsers still can't use location.
I did not see the other things you mentioned. My calendar, which is the default version, doesn't have preferences. I don't see a detailed custom latitude and longitude either, other than "Europe/Berlin" which refers to the timezone but not exact position.
I booted a Mate 20.04 DVD to realize an untouched Mate won't have working browser location either. So it seems Mate is not shipping with browser location by default.
I don't know how to proceed. I am not an expert. I would be thankful for a step-by-step instruction to get this to work in Ubuntu Mate. Does anyone use it on a LAN connection and/or it is working?
Add the clock to your panel if not already there. Where the time and date appear right click that. In the middle of the pop up it should say preferences. There will be three tab, General, Locations and Weather. Click the middle tab, Locations, on the right will be a button, Add, with edit and remove grayed out until you add the Location Name, Timezone and latitude and longitude.