Who sees this?

In the portal, under Environments, click Development, and there Open. Flow opens in a new tab and you are signed in straight away.

In the explorer, hover over the dashboard and click the icon with the people (Who sees this). The window lists at the top who can open it: the roles, the teams and groups, and the people themselves.

Next to each person is the chain: the role that gives access, and how they have that role. Sanne is an Employee, and that is not enough: the dashboard now reads a confidential table. She can open it anyway, because she is in the team Sales, which has the role Reader.

Below is who has the dashboard in their menu on the home but cannot open it. Tom is an Employee and is not in Sales: since the table became confidential, he may no longer see it. That is not a hole (Flow checks every opening) but a broken link: remove the item for his audience, or give that audience access. At the bottom, per role, is why it may not.

For an AI Colleague too you see who may chat with it and why. Everyone with a role that may chat can open it as long as the chat is on and it is published. To limit it to a few roles, set them in the AI Colleague's chat settings; the panel shows it straight away.