The location information is from your phone and network provider ... not Google.
You can find where you are on open street map or other map provider.
I find the technology a bit annoying because, in most cases, I don't want the web site to know my location.
Any web site can request that you give you location. The accuracy of the information usually depends on your provider.
Fully true, the point is having a simple to remember way for any place on earth to find your place back. https://whenwhere.cf is a fully open source webapp written by me that runs on IPFS so it doesn't even reach any of my servers, it doesn't send anything to any server and gives you the plus code of your current location and enables you to navigate pluscodes. I created this so people don't depend on Google. That said, Google did invent this system (for completely free usage by everyone, all related source code is APL and the code system itself doesn't have any form of encumberment). At this point only openstreetmap.org didn't implement the codes (derived systems do, e.g. OSMAnd and Mapy.cz both use OSM maps) and you can find on my Github some bookmarklets that remedy this for the OSM website. If you know your location you can even calculate plus codes by hand.
The Plus Code system is meant for places without clear and simple to use street names and house numbers, as is still the case in a surprisingly huge part of the world. I have written about them before. The idea is that you can easily communicate your location to enable e.g. logistics, emergency services etc where to this date communication of your location is very hard. As many people use Google Maps, giving this code immediately on the "Where are you?" screen is very useful.
I want to parse a hair here. Google did not invent GIS technology, nor did they invent advertisement driven maps (Googles maps are driven by ads). They simply extended their monopoly in search to maps.
Google did create the thing where cars drive along along roads taking pictures of the road. They aren't completely bad, I think people need to avoid the trap of claiming that Google invented GIS.
PS: I used GIS software a decade before Google was created.
I also should reiterate. OpenStreetMap is a open source map project.
I am talking about neither. I am talking about OLC, Open Location Codes, aka Plus Codes, invented by Google Zürich. read about it on https://plus.codes