What to ask for at handover.
Everything you need to build, run and change the product without the supplier: native files, source code with its history, accounts in your name and the test results. Print it, tick it off, and do not sign the last invoice until every line that applies is done.
Tick each line as you receive it. Nothing you tick is stored or sent anywhere.
whitehatdesignstudio.com/handover-checklist, rev 1.0. Free to copy into your own contracts.
Tell us what has to work.
One sentence is enough. An engineer will reply.