Domain format in "Disable read HTML5 canvas" Exceptions list

[Fish David B. Trout]

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What is the format for domains entered into the Exceptions list of the "Disable reading from HTML5 canvas" option? Are wilcards allowed? Can I enter a value such as "*.example.com"? Or: "example*.com"? Etc?

Slimjet allows me to enter such values into the list, but my question is will they actually work as expected? Or will they be silently rejected?

I don't wish to waste my time experimenting and trying various different values/combinations over and over and over again.

So what's the rule?

Thanks for a great product!