Ask HN: How are Engineering Managers evaluated?

So we all probably know how Software Engineers get evaluated (performance review): In companies that have a process for this, every 6 or 12 months you have to

- fill out self-assessment

- ask peers to fill out an assessment for you

- 1:1 with engineering manager to discuss your assessment(s)

- engineering manager discuss your sitation with "upper management"

- if lucky, you get a promotion/salary raise

In young companies that do not have such a process, you may get a promotion/salary raise in a more informal way.

My question is: what's the process for Engineering Managers to get promoted/salary raise? In my years of experience I have never "rated" or assessed an engineer manager (I have given feedback, but to them directly). Who's evaluating the eng. managers? Upper management? But based on what?

In all the companies I have worked for, the best ones are very transparent regarding promotion and salary ranges but for engineers only. When it comes to eng. managers, it's all very secret (they even have their own private Slack channels and all).