Where is info.plist for React Native projects run in Expo for the purpose of callback URLs?

For non-Expo projects, the location is /YOUR_APP_DIR/ios/YOUR_APP_NAME/Info.plist. If you update this file and save, you will see the same file update in Xcode.

Shubhnik Singh truly helped me out here. For anyone wondering, go here: https://docs.expo.io/versions/latest/workflow/linking/

More specifically, look at the Expo.Linking module section. Instead of creating your own callback url link, you are borrowing Expo's. You are, after all, running everything from with inside another app, so it wouldn't make sense to have your own true callback link.

In all, you do have a callback link that Expo gives you.

Edit: Saturday, March 30th, 2019

As reported in the comments, the original link to the Linking guide is dead. But, it only appears like Expo moved around some stuff on their domain. It is apparent that some of the actually details have slightly been changed (see WayBackMachine's snapshot of the original page). Specifically relating to this question, the callback URL specifics and the names on the actual guide have changed slightly. I have updated my original answer above to reflect this.