Today in History has no account, no server of its own and no analytics or advertising code.
What the app sends
The app talks only to Wikipedia and Wikimedia, run by the Wikimedia Foundation:
the day's "On this day" list (the month and day you look at),
the photos for it.
These requests carry no account, no identifier and nothing about you; like any request on the web, they reach Wikimedia from your internet address. Wikimedia's own privacy policy covers how it handles them. When you open an article, it opens in Safari, on Wikipedia.
What stays on your iPhone
The days and photos you have looked at, so they work offline.
Your quiz answers, scores and streak.
A few counters for the app's own numbers screen: which days you opened the app, on which you played the quiz, how many articles you opened, how often you tapped the widget. Days only, no times, no content.
None of this is sent anywhere. Deleting the app deletes all of it.
What we do not do
No sign-in, no email, no contacts, no location, no photos from your library.
No tracking across apps or websites, no ads, no data sold or shared.