Oh, shut up and help me remodel the Amazon Appstore page!
The Amazon Appstore (full name Amazon Appstore for Android), previously Amazon Underground, is an application portal curated by Amazon.com Inc. exclusively for Android-based mobile devices. The Appstore provides an alternative source of software to Google Play, and acts as the primary distribution medium for Amazon.com's own Fire line of devices. As part of an agreement with Canada's BlackBerry Ltd., it acts also as a secondary source for BlackBerry devices via the BlackBerry 10 operating system's Android compatibility layer.
During much of 2016 and early 2017, the Amazon Underground service operated as both an app store and a mobile storefront for Amazon's retail goods. These functions were split and restored to their original formats effective May 2017, sunsetting the Underground format by 2019.