Extract all Rules from Plot function

Let’s say I would like to know all the Rules that apply to PlotTheme->"Detailed". I tried

Select[FullForm[Plot[x, {x, 0, 1}, PlotTheme -> "Detailed"]], Head[#] == Rule &, Infinity] 

but I get the Error/Warning that FullForm was called with 0 arguments, which doesn’t make sense to me. What would be the correct way to do this?