What evidence do you need before buying an iOS source-code project?

I'm the maker of YXC Code, a store for commercial iOS app source-code projects. I'd like to improve the information developers see before deciding whether a project fits their needs.

If you have bought a source-code project, which evidence mattered most before purchase: a clean-build video, an exact file/dependency inventory, a customization walkthrough, or clear licensing and support terms?

For example, an App Store demo can help you evaluate the app's behavior, but it does not establish which files or source version are delivered. We have published a free evaluation checklist here: https://github.com/yxcit/ios-sou...

Our store is https://app.yxcit.com/en . The checklist repository contains educational guides only; the paid app source is not open source.

What is the single missing detail that would make you stop considering a source-code purchase? Specific examples would help us prioritize what to document next.

Disclosure: posted by the maker; wording prepared with AI assistance.