[jevanish]

A lot of employees either A) don't know what to talk about or B) aren't sure what their current manager considers safe topics.

Questions like the above (though not all of them) can help spark discussion and get them to open up. I've personally seen a number of times where team members have a lot to say about something and didn't realize I wanted to hear their ideas on that topic.

Obviously, delivery matters, and choosing a good question is important. If you have a foundation of trust already built (see Psychological Safety research) then a lot of those questions can help.