Document? Sprinkler app. Web Page? Sprinkler app. Installing from a source other than Google? Oh you better believe the sprinkler app can do that.

Android apps tell the system which URLs they can open. If you click a Google Maps link, it can prompt you to open it in the Google Maps app. It sounds like whoever created the sprinkler app misconfigured the app and it’s saying that it can open all URLs, not just the URLs it cares about. They probably read a tutorial about how to make a webview in Android and didn’t know what they were doing :)