From the few tests I conducted, I see that this extension is doing what it is supposed to do well. Well done. Its font is large and readable, and the extension's UI adapts to the system theme. Last but not least, it doesn't request any special permissions.

I think everyone might need this extension at least once or twice in their lives, even if they don't know it. We are bound to run into websites that incorrectly detect our regional language (or worse, offer a poor translation). In some of these cases, editing URL tokens could help a lot. For example, in the case of Google, adding the "hl=en" to the URL (or modifying the "hl" parameter to "en") helps.