Is it possible to filter blocks based on colors?

i am confused. i am not having any pdf or epub file. i am looking for a solution for nomal blocks that have been colored using the default feature of right clicking and choosing from the colors available.

also i am curious, i why does it have h3 in the code? because none of my blocks are heading 3. is it something related to the color just above the heading number? if so, the color above h3 is pink, not red.

also, I copy pasted your text it gives out nothing. the screenshot is when I am NOT in editing mode.