> I have found this extension helpful for helping mitigate WebGL fingerprinting on Firefox — https://addons.mozilla.org/en-US/firefox/addon/webgl-fingerp...

It might work for simple fingerprinting scripts, but not for anti-anti-fingerprinting scripts. See: https://palant.info/2020/12/10/how-anti-fingerprinting-exten.... Since you're already on firefox, you're probably better off enabling resistfingerprinting instead.

Getting a random value each time is trivially detectable. That's a better signal that what you're blocking if more people share your video card model than install the extension.

It fails the first section ("Barking the wrong tree"). If I install the addon and then run

    gl.getParameter.toString()

I get

    "function () {
              window.top.postMessage(\"webgl-fingerprint-defender-alert\", '*');
              //
              if (arguments[0] === 3415) return 0;
              else if (arguments[0] === 3414) return 24;
              else if (arguments[0] === 36348) return 30;
              else if (arguments[0] === 7936) return \"WebKit\";
              else if (arguments[0] === 37445) return \"Google Inc.\";
              else if (arguments[0] === 7937) return \"WebKit WebGL\";
              else if (arguments[0] === 3379) return config.random.number([14, 15]);
              else if (arguments[0] === 36347) return config.random.number([12, 13]);
              else if (arguments[0] === 34076) return config.random.number([14, 15]);
              else if (arguments[0] === 34024) return config.random.number([14, 15]);
              else if (arguments[0] === 3386) return config.random.int([13, 14, 15]);
              else if (arguments[0] === 3413) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 3412) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 3411) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 3410) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 34047) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 34930) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 34921) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 35660) return config.random.number([1, 2, 3, 4]);
              else if (arguments[0] === 35661) return config.random.number([4, 5, 6, 7, 8]);
              else if (arguments[0] === 36349) return config.random.number([10, 11, 12, 13]);
              else if (arguments[0] === 33902) return config.random.float([0, 10, 11, 12, 13]);
              else if (arguments[0] === 33901) return config.random.float([0, 10, 11, 12, 13]);
              else if (arguments[0] === 37446) return config.random.item([\"Graphics\", \"HD Graphics\", \"Intel(R) HD Graphics\"]);
              else if (arguments[0] === 7938) return config.random.item([\"WebGL 1.0\", \"WebGL 1.0 (OpenGL)\", \"WebGL 1.0 (OpenGL Chromium)\"]);
              else if (arguments[0] === 35724) return config.random.item([\"WebGL\", \"WebGL GLSL\", \"WebGL GLSL ES\", \"WebGL GLSL ES (OpenGL Chromium\"]);
              //
              return getParameter.apply(this, arguments);
            }"

without the addon I get

    "function getParameter() {
        [native code]
    }"