Maps Region Switcher per mfcallahan

This extension sets Google's own gl (region) query parameter on Google Maps page loads, so Maps renders exactly as it does for a region you choose, using Google's real rendering, not an overlay or a patch. Pick a region from the toolbar popup and toggle it on or off at any time.

Google Maps already varies certain place names, business rankings, attribution text, and interface language by region. This is Google's own behavior, not something this extension adds or changes. This tool simply lets you view that regional variation from wherever you are, which is useful for travel planning, research, or simply understanding why a map looks different for someone in another country.

How it works: two static declarativeNetRequest rules add or replace the gl query parameter on top-level Google Maps navigations, and allow-list URLs that already carry the parameter to prevent a redirect loop. Only the query string is touched, nothing else about the page is modified, and no content is injected or altered.

The extension requests no data, transmits nothing, and only acts on Google Maps page loads. It is scoped to three narrow host patterns: www.google.com/maps, google.com/maps, and maps.google.com.

Source: https://github.com/mfcallahan/maps-region-switcher