the Bing search engine inclusion deal Opera Software had with Microsoft just expired and MS decided to not renew or pay the value Opera was asking for it. Opera then replaced it with DuckDuckGo either because they made a deal with them or by "philanthropy".

I doubt this considering that it is still included as the search for "define *".

I believe it's too lazy for developers to remove the code at that moment.

My phone is Lumia 1520. I choose 400% to zoom in page. But the text and icon inside Opera is still small. On some Chinese websites, such as weibo.cn and wapp.baidu.com, Chinese characters slip and overlap which looks like a far early bug in opera mini. Hope Opera better.