A handover is not a zip file. It is the difference between a site you own and a site you are renting from the person who built it.
On every build it means the same four things. The domain is in the client’s name. The code is in their repository, with a README that explains how it runs. There is a recorded walkthrough of how to edit content and deploy. And there is a month of fixes on me, because the first month is when the real questions appear.
I also leave a validation script. It checks every page, image, font, script, sitemap and robots file, and it runs green or it tells you what broke. It is the cheapest insurance a small site can have.
If I disappear tomorrow, the site keeps running and the next engineer has a fair chance. That is the standard I want to be held to.