Opera Mini has had its fair share of problems in the Windows Phone store. It's been unpublished on a number of occasions in the past. It even went missing while it was in beta form a few months back. Now it has yet again been removed from the Windows Phone store.
This time the removal was as spotted by Windows Central. There's no word on why it's missing from the app store, but Opera has confirmed that they are working on the issue to bring back the app as soon as possible.
@JCalMN Yes, we are currently working with Windows on the issue. Sorry for the inconvenience! /Kendra
— Opera (@opera) July 27, 2015
Opera Mini is quite a popular browser, especially on mobiles. However, things are a little patchy for it when it comes to Windows Phone. In the past, Opera has clarified the issues they've had but they didn't mention details on why the app was removed this time.