@Swacsa

How can I figure it out?

You appear to be a accessing the board as a Visitor and only members of the team in which the board resides will see the Board Owner info. that being said, there is no way for you to identify the board owner – or at least there is no way that I could find (which is surely by design).

A few options would be to add a HUGE sticky note to the board with a note asking that the board owner reach out to you. Another option that could draw more attention to those opening the board is to leave a note in the Visual Notes panel and then pin it open:

A few things I noted:

• in your screenshot, you do not have a Leave button, so you are accessing the board as a Visitor, which means the board history and @mentions are not available to you.
  • Even if you were on the board as a Guest, you would still not see the “board owner” in the board details windows. You would, however, be able to @mention other team members, including the board owner, but the roles would not be present to you. You would also be able to see the board history-activity, which will not show the roles/board relationship of those who’s activity was captured.
• I also noted you have the Duplicate button, so if you were looking to duplicate/copy the the board to your own account, you could. The button is present because the board’s content settings are configured to allow for anyone with the board access to copy it.