Is there any update on an official way to do these block lists? I see there is now a validator that checks the format of your block list when you add it. Mine was invalid until I put the following header in the text file:
[Adblock Plus 2.0]
Even after doing this all my rules that work fine in uBlock Origin seem to have no effect when used in Opera's built-in blocker. My understanding is that both use the easylist format.