The vigil and this iPhone
The Wake collects a device ID. It is not linked to your name. It is used for tracking. The purposes are analytics and the function of the app. No other category of data is collected.
Before that identifier is read, the iPhone asks. Allowing the question lets it leave this phone. Tracking uses it, and analytics uses the same value so one installation of The Wake can be told from another. A name, a relic, and a night's memory are not stored with it. Declining leaves it unread. You can change the choice afterward from the iPhone's Settings, by opening Privacy & Security and then Tracking.
This app writes an install number into the keychain. It also reads the vendor identifier the system provides. Both are device IDs, and both can leave the phone so a fresh install of The Wake can still recognize this iPhone. That recognition is app functionality. Delete The Wake and install it again, and the keychain number may still be there. It is not a name.
Nights, relics, the memory book, guest notes, and the lamp settings stay in the app on this iPhone until The Wake is deleted. They are not sent. The keychain number is the item that can outlast that deletion.
Photos, precise location, coarse location, payment details, a contact list, a phone number, an email address, and a name are not collected. The Wake does not open an account.
Children are not the audience for The Wake.
To reach the developer, open the support page.