Android版FirefoxでChromeと同じGoogleのUIが使えて便利です。

Good

Thought I was in the add on manager.

You need to add the "x" on the right side of Google's search box in order to clear the textbox at once.

Firefox android without the Google Search Fixed add-on shows the "x" as does native Chrome app on android.
Using this add-on the "x" is missing.

易于使用

Great!
Adding support for Facebook would be great too!
Facebook lowers the image quality for mobile devices' browsers to force you use their app.
However, using a Windows 10 Chrome user agent on Facebook(even on the mobile version) unlocks all features!

"Access your data for all websites" why?

Good