of being blacklisted.

-   Anzhi. Anzhi, the largest alternative market of our dataset, is operated from China and targets the Chinese Android user base. It stores and distributes apps that are written in the Chinese languages, and provides a less strict screening policy than that of Google Play.

-   AppChina. AppChina, another Chinese market, has used to enforce drastic scraping protections such as a 1Mb/s bandwidth limitation and a several-hour ban if using simultaneously more than one connection to the service.

-   F-Droid. F-Droid is a repository of Free and open-source Android apps that users can download and install on their devices. Many of the apps found on F-Droid are modified versions of apps that are released to other markets by their developers. The modifications brought by F-Droid are usually linked for example with advertisement.

Metadata Collection {#sec:metadata_collection}
===================

Our objective in this work is to facilitate the access of AndroZoo by providing to the research community not only a large set of Android apps but also sufficient metadata associated with those apps. Users of AndroZoo can therefore to pre-select a set of apps that are all relevant to their research. As a result, only those selected apps need to 