Unfortunately, I don't think it is possible to investigate who favourited your dashboard on Tableau Public! It's a bit annoying, but kinda makes sense.
Sorry I couldn't help further - perhaps submit this to the Idea part of the Community? https://downloads.tableau.com/tssoftware/TableauReader-32bit-10-4-4.exeIdeas
I hope this is useful at least
Thanks for your answer. I thought that this is the case, but wanted to make sure.
Not at all! Glad to have helped.