Does core currently support any block previews by convention.. eg if I have a element type of GridBlock could that automatically use a

/App_Plugins/BlockPreviews/GridBlock.html

without explicitly having to wire up all the blocks via setting the

grid datatype> block> advanced> customview.

(or indeed use the blockname and fall back to the doctype element name. Indeed the same for custom css, either a default always include this

common css

... or

css/BlockPreviews/GridBlock.css