20.2.28 and possibly later versions added a class refined-github to the <html> node which we use at GitHub Dark to scope RGH-specific CSS rules. On 20.3.3 (Firefox), I only see a class=" " (double space) being added. Could you please restore the old class again?
Related: https://github.com/StylishThemes/GitHub-Dark/issues/1082
20.3.3 ist broken. See: #2856
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20.3.3 ist broken. See: #2856