Check for "Extract Canvas Data" permission.

[FssAy]

Page: Terminal

Without the "Extract Canvas Data" permission text on terminal is bugged (#19345). As the @AliAsgerSaify mentioned, it's easily fixed by just granting the permission, but for some users it might not be straightforward as there are no indicators other than a small icon on the URL bar (Firefox based browsers).

In my opinion it might be a good idea to check if the permission is granted and if that's not the case - show some kind of an error or prompt to inform the user.

[martinpitt]

Same question as we already had in #19345 -- which extension does this? Standard Firefox most certainly doesn't do that, at least not on Linux. This is obscure enough that we can't just fix this blindly, we'll need to be able to reproduce.

[FssAy]

From what I see it's a setting option in the Firefox based browsers (I am not sure about Chrome and others). Some privacy focused web browsers like LibreWolf have this setting enabled by default. What is more, there are also privacy based extensions which blocks usage of canvas.

I've just looked around and found a script that checks if the canvas is blocked: https://github.com/johnozbay/canvas-block-detector This repo's readme also explains a lot of the issue.