One of the users of my add-on GroupSpeedDial has a problem that I was not able to reproduce so I asked him to send me console logs from background script and there I saw several lines like this one:
Firefox nedokáže vytvoriť pripojenie k serveru ws://127.0.0.1:1001/?cid=624950170. background.js:20:122
Translated to English - “Firefox cannot create connection to server ws://127.0.0.1:1001/?cid=624950170. background.js:20:122”.
Now the interesting part is that my production file “background.js” has only one line (so there cannot be error on line 20) and there is no Web-Socket in my whole add-on at all.
So the source code had to be modified. But is this even possible? And for what purpose?