This web-extension breaks down the Geolocation-interface, unlinking all methods such as <code>getCurrentPosition</code> and <code>watchPosition</code>, 
<a href="https://developer.mozilla.org/en-US/docs/Web/API/Geolocation#Methods">developer.mozilla.org/en-US/docs/Web/API/Geolocation#Methods</a>. 

This web-extension will work on each and every hidden IFRAMEs and document, regardless of "tricks" some vendors will try to do.
This web-extension breaks-down the JavaScript support for using anything related to GeoLocation.

This web-extension will also use a an injected "feature policy" (<a href="https://developers.google.com/web/updates/2018/06/feature-policy">developers.google.com/web/updates/2018/06/feature-policy</a>), 
pretty early in the page's life-cycle setting <code>GeoLocation</code> to <code>None</code> through the browser internal permission system. This is experimental but it is another way to help with GeoLocation blocking.

Note1:
while Chrome DOES allow web-extensions to run their JavaScript even when there is no-JavaScript support on the page (either disabled by the browser or "Policy HTTP Header"), 
On Firefox - if there is a some kind of rule that prevents external-javascript to run on the page, this web-extension will no work.

So - on Firefox, it is best if you'll add the following restrictions in the <code>about:config</code> section:
<code>geo.enabled</code> - <code>false</code>
<code>geo.wifi.logging.enabled</code> - <code>false</code>
<code>geo.wifi.uri</code> - <code>https://0.0.0.0/</code>
<code>geo.wifi.xhr.timeout</code> - <code>1</code>

Note2:
web-extensions can also access the GeoLocation API, without 'walking-through' the page's own JavaScript engine, 
https://developer.chrome.com/extensions/declare_permissions
they can do so even without asking from the user to allow geolocation-pin pointing, and there is very little to do once you've installed one of those.. so beware.