I've seen the same thing and in the last few updates there's been no fix which means they are probably unaware of it or it is a Linux only issue.
Latest posts made by tharrisone
RE: Extension icons on Opera 25.0.1583.1Opera for Linux
How do I move around extension icons on the main bar?Future releases
Ok, maybe I have ocd or I'm just seriously picky but I need certain extensions to be first/second/third. I was a die hard opera users for years but the Linux version was recently released.
My other issue is that I only have a few preselected search engines that can be made default. I need my Duckduckgo or Startpage to be default. I've setup hotkeys but I often forget
Opera-developer: Identifying backend connectionsFuture releases
I've always had reservations using Chrome/Chromium because of all the Google remote connections and WebRequest API crud beyond most users knowledge.
After looking at all net activity I've only been able to identify a few opera services.
The sitecheck host is a malware domain checker that uses http instead of https but it has no option to disable.
The others are understandable if you want updates or to install/update an extension.
It's great to have a webkit/blink opera browser(especially for me in Linux) that isn't heavily leaking out my personal data. I'll keep monitoring tcp/udp connections just in case but I've already made the opera-developer version my default browser.