Time zone estimation
GMTcheck online allows you to know in most of the cases, the time zone where the app comes from. It uses two different techniques described in the paper below.
Files metadata, domains and cert info
Using GMTcheck online, you can extract at the same time, useful information about the existing metadata from files included in the app, domains in the app code and all the information from its certificate with significative information highlighted.
GMTchecker extracts information related to the geographical context of the app, such as the languages to which the application has been translated.