Have you read the “End-user license agreement and terms of service for Opera for desktop”? There seems to me to be some questionable language there, especially regarding third party software included, and and also “out of country” storage of your data.
This sounds like a spyware program to me.
"The source code modified by Opera is available for download at http://sourcecode.opera.com/gstreamer/."
Feel free to peruse it at your leisure, but since uncounted 'nix geeks and slashdotters have been doing so for at least fifteen years I think you can relax about any potential spyware being part of it.