Like the parent said, typically it works like: - browser ships a feature X - they decide that X shouldn't be allowed in incognito (or that incognito mode retu

Like the parent said, typically it works like: - browser ships a feature X - they decide that X shouldn't be allowed in incognito (or that incognito mode returns fewer values, has lower quotas, uses different implementation that is slower/faster etc.) - inadvertently, this becomes incognito detection vector - people report the issue; the feature X is fixed - another thing is shipped which accidentally allows detecting incognito - ad infinitum