Wikistats (https://stats.wikimedia.org/#/en.wikipedia.org/reading/unique-devices/normal|line|2-year|access-site~mobile-site*desktop-site|monthly) breaks out unique devices by Desktop Site and Mobile Site, is a count for Mobile App available (as it is for pageviews) and how do we get access to that data? If not available through Wikistats do we have a way to extract these counts?
There are no Unique Devices counts for mobile apps computed the same way they are for the desktop and mobile sites (i.e. all requests are counting towards the total) because the methodology was never implemented in the IOS and Android apps. See ticket where counting methodology is described, filed in 2018: T202664: [EPIC] Count unique iOS & Android users precisely and in a privacy conscious manner that does not require opt in to send data
There are unique counts for both iOS and Android apps that are opt-in (and, as such, incomplete) in the table mobile_apps_uniques_daily