My baseline would be similar to that which you get from modern compilers and automated tests. Something like:
Lib/urllib/parse.py contains disallowed string "itms-services" at line 62 column 25
Reason: Apps may not install or launch executable code, such as through the itms-services URI schema.
To get credit for "giving you a clear direction", I'd want them to make available and suggest a fix. In general that could be "if this is a false positive, click to request a human reviewer make an exemption" but ideally monitoring for this kind of issue in the first place (sudden increase in identical rejections) and fixing the broken check.
Instead, Apple seem to omit the information on the first line that they likely already get from their internal tool, and not only don't suggest a fix but make the proper fix so unavailable that it's easier to get the language itself changed than a check in their review framework.
> But it has been known for over a decade now that Apple searches binaries for strings. They've never done runtime execution checks which would pick up you actually making such an HTTP call.
It's true that someone with folk knowledge about the way Apple does checks, gleaned about the process by other frustrated users, could likely infer the way in which Apple's test is broken and so eventually deduce the first line from the second line. That's not Apple giving a clear direction - that's developers managing to work around an inscrutable system.