IANAL, but working in a trading desk and have 3/4 compliance trainings on insider trading every year (for SFC/HK and ESMA/Europe).

My understanding is the same as the parent post. You are assumed to know what is private information and what is not. A number of things are considered to be explicit markers of "public", e.g. the information is available on a platform that is freely accessible to anyone. In case of doubt, recommendation is to ask a local compliance officer.

So in summary, you are supposed to know, or to have the means to know (through compliance dpt). Anyway, if working in finance, there's a 99% chance you have to pre-declare and get approval for your single names stock purchases, and are subject to a minimum holding period.