What belongs in an app handover before the developer steps away?

I’m Kayne, the maker of Keeplira. I’m working on a practical owner’s manual for apps and websites, and I’d like feedback from people who have been on either side of a handover.

My baseline checklist is:

1. A named owner for the domain, hosting, payments and any other service the app relies on.

2. The dashboard link for each service and instructions for requesting an individual account invitation.

3. Fixed costs, billing intervals and renewal dates, with variable charges called out separately.

4. The steps to check before a release, plus where to find the last working version or a backup.

5. A support contact and a clear statement of what ongoing maintenance covers.

6. A downloaded copy of the guide, so the information does not depend on a shared link staying active.

Passwords and API keys should stay in a password manager. The guide should explain how an authorized person gets access.

Keeplira’s beta organizes manually entered service details and notes, offers Markdown downloads, and lets the owner share a revocable read-only guide. The fictional example is open to explore without an account: https://keeplira.kaynewayne.chatgpt.site/

Which item would you add to this checklist because it caused a real problem in a handover?