Actually it's not a subset. Even if the app is open source, what you gain from this error is: username, installation path, resource limits. All of those add something you don't know from the code itself. All can be useful when trying (respectively) injections / bruteforce auth, path traversal / secrets access, denial of service.
Also line numbers can help you identify the deployed version.
Also optional table prefixes which are deployment-specific.
Re:Malls Aren't Dying, They're Thriving
by dragonwriter on Monday June 08, 2015 @11:52PM
(#9683978)
You're right, I was wrong; leaving the grandparent post just for context for your response, otherwise I'd delete it.
Information leakage is considered a security vulnerability. https://www.owasp.org/index.php/Information_Leakage
If this is a security complaint, well, its less exposed information (a strict subset) than if your app was open source, so I don't see it as particularly a problem.