What does the keys icon mean on a Dashboard? Why do they show up for certain users and not me?

I'm the admin of our Metabase instance. I've setup all the dashboards and questions. Some users have reported seeing the below image of "keys" on their dashboards in lieu of certain questions. I'm not able to reproduce this nor login as them so i'm unsure what this image of "keys" means. Any guidance here would be extremely helpful. Thank you!

Hi @abelsonlive
Because the users don't have permissions to the question. I would recommend reading through this article, which describes the collection permissions: