https://forums.opera.com/topic/23791/how-to-have-my-website-on-mobile-opera-browser-feed/6

I tried the latest Opera for Android 44 stable (44.1.2246.123029). Unfortunately, I still cannot open web links in associated apps (e.g., YouTube, Google Maps). If this already worked in the Beta, I really hope that this feature will be added (or the "bug" will be fixed, however you see it) to the stable version in the near future, because I clearly see a case for this one.