Hier der Ubuntu-Firefox Ausdruck, falls es weiterhilft. Der Fehler liegt sicher daran, dass Skriptcode von Google Analytics eingebunden wurde.

NodeList [ html
]
Unknown pseudo-class or pseudo-element ‘-moz-scrollbar’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:1:8273
Unknown property ‘speak’. Declaration dropped. MQTT_vs_HTTP_API:12:784
Unknown property ‘-moz-osx-font-smoothing’. Declaration dropped. MQTT_vs_HTTP_API:12:956
Error in parsing value for ‘cursor’. Declaration dropped. MQTT_vs_HTTP_API:12:3947
Unknown property ‘speak’. Declaration dropped. MQTT_vs_HTTP_API:12:37099
Unknown property ‘-moz-osx-font-smoothing’. Declaration dropped. MQTT_vs_HTTP_API:12:37251
Unknown pseudo-class or pseudo-element ‘-webkit-full-screen’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:41201
Unknown property ‘-moz-osx-font-smoothing’. Declaration dropped. MQTT_vs_HTTP_API:12:7319
Error in parsing value for ‘-webkit-text-size-adjust’. Declaration dropped. MQTT_vs_HTTP_API:12:7354
Unknown property ‘-moz-osx-font-smoothing’. Declaration dropped. MQTT_vs_HTTP_API:12:7819
Error in parsing value for ‘-webkit-text-size-adjust’. Declaration dropped. MQTT_vs_HTTP_API:12:7854
Error in parsing value for ‘min-height’. Declaration dropped. MQTT_vs_HTTP_API:12:33547
Error in parsing value for ‘overflow’. Declaration dropped. MQTT_vs_HTTP_API:12:34557
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:41361
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:41538
Unknown pseudo-class or pseudo-element ‘-webkit-autofill’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:41910
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:42349
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:42462
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:42805
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:12:42916
Loading failed for the with source “https://www.google-analytics.com/analytics.js”. MQTT_vs_HTTP_API:1:1
Error in parsing value for ‘overflow’. Declaration dropped. 2 MQTT_vs_HTTP_API
Error in parsing value for ‘min-height’. Declaration dropped. MQTT_vs_HTTP_API:7:15
Error in parsing value for ‘overflow’. Declaration dropped. MQTT_vs_HTTP_API:93:13
Unknown property ‘-moz-osx-font-smoothing’. Declaration dropped. MQTT_vs_HTTP_API:5:27
Error in parsing value for ‘-webkit-text-size-adjust’. Declaration dropped. MQTT_vs_HTTP_API:6:29
Unknown property ‘-moz-osx-font-smoothing’. Declaration dropped. MQTT_vs_HTTP_API:5:27
Error in parsing value for ‘-webkit-text-size-adjust’. Declaration dropped. MQTT_vs_HTTP_API:6:29
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:57:21
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:62:21
Unknown pseudo-class or pseudo-element ‘-webkit-autofill’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:79:21
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:89:74
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:92:74
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:101:80
Unknown pseudo-class or pseudo-element ‘-ms-input-placeholder’. Ruleset ignored due to bad selector. MQTT_vs_HTTP_API:104:80
Error in parsing value for ‘animation’. Declaration dropped. MQTT_vs_HTTP_API
Error in parsing value for ‘animation’. Declaration dropped. MQTT_vs_HTTP_API
Error in parsing value for ‘animation’. Declaration dropped. MQTT_vs_HTTP_API
Error in parsing value for ‘animation’. Declaration dropped. MQTT_vs_HTTP_API
Error in parsing value for ‘animation’. Declaration dropped. MQTT_vs_HTTP_API
Error in parsing value for ‘animation’. Declaration dropped. MQTT_vs_HTTP_API