Update: This problem has now been resolved! The app now displays individual Stack Overflow webpages in the user's browser, rather than in WebViews. Since the details are likely to be of most interest to fellow developers of Stack Apps for Android, I've posted more information in the related post there.
I wrote a little Android app (Stack Flower) that allows customized searches of Stack Overflow. It uses the Stack Exchange API to find matching results, and then if the user clicks on one of the results, the app displays the relevant post in a WebView. I thought that this was fine, especially since there are several other apps that do the same thing, but now the Google Play Store is demanding "verifiable documentation" indicating my rights to use the content in my app.
As I understand it, Stack Exchange welcomes projects that link to its content (hence the Stack Exchange API and the Stack Apps subsite). However, I can't seem to find an official statement saying that it's okay to link to Stack Overflow from within apps, even though the answers to questions like this strongly suggest so.
The Trademark Guidelines state that all user-generated content is available under a CC license, and the API (which I use with an authorized key) returns both the user-generated content and all of the associated metadata. Therefore, all of the content needed to display a post's webpage seems to be openly available to apps that use the API... and if an app that uses the API does violate Stack Exchange's guidelines, it can be easily killed by simply disabling the API key.
So I didn't believe I was doing anything controversial by displaying the relevant webpages in my app (especially since there were already other apps with thousands of downloads doing the same). But I'm unable to find an explicit statement that it's okay to link to individual question/answer posts from within an app, which is what Google needs to see. And now I'm worried.
I had always intended the WebView as a temporary placeholder, to get a "minimum viable app" out the door. I was already working to get rid of the WebView in the next release and replace it with a much prettier display (custom-built from the API). But since the only problems I saw with the WebView were aesthetic, I went ahead and released what I had. It hadn't even occurred to me that this decision might put me on shaky legal ground.
My situation seems even more precarious, since there's now an official Stack Overflow app for Android (which was announced on Stack Apps about a week after I released my little app). If the official app offered better search customization, it would make my own app obsolete, and I'd willingly delete it from the store myself. But until then, I think there's a niche for an app that provides better search customization, and I'd like to keep my app alive.
All I ever wanted to do was provide a useful little tool. Please help me, if possible.