After installing it I tried with various sites that show the referer, it works (show referer = "blank")
The only flaw is that the icon on the bar is not visible (it seems transparent) but this is not a big problem.
I wish a plugin like this was available as standard on Firefox.

It works perfectly! Thank you for this great addon

Simple and easy. Works as expected but it should be nice to have a whitelist and a choice of different SVG images.

Works flawlessly as advertised, but I suggest some configuration option to finetune its behaviour: reset to a selectable default state when opening a window, and a whitelist/blacklist scheme. Some sites refuse to work without the proper referrer (authentications for the most part) while on others I don't want to leave it on by mistake. Configurable spoofing might be nice to have too, but probably isn't worth the complication.

New change is bad. Please add an option to disable Spoofed mode as a toggle and an option not to save button state. I'll update my review. Thanks.

Very nice!

Working with a whitelist would be nicer. As suggested in my previous review,

https://addons.mozilla.org/addon/referrer-switch/reviews/1119735/

Thanks again

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Postscript, 2019-12-29: now using Smart Referer,

https://addons.mozilla.org/addon/smart-referer/

Fa quello che promette ma probabilmente un icona diversa, più visibile sarebbe auspicabile.

It just works.

Nice add-on, but the icon is seriously flawed. It has a transparent background, so with a dark theme it's next to impossible to see if it's enabled or disabled. The only difference between the enabled symbol and the disabled symbol is a short break of a one-pixel-wide black line and the break is just a few (maybe 3) pixels long. Fix the symbols, to make it visible maybe add colors, red and green would be fine.

Works well and easy.
Thank you

please make more universal icon