I think post this is generally well understood. The question has
always been how to parse the phrase "Known icing conditions". Is it
"(Known icing) conditions" or "Known (icing conditions)". It makes a
huge difference whether its illegal to fly in any thing that is known
to maybe make ice (we understand very little about why ice forms) or
is it ok as long as you know the conditions aren't making ice (i.e.
PIREP).

BTW: Accoring to your FSDO, it is legal for a J-3 cub to fly in "Known
Icing Conditions" because no such limitation exists in its
certification.

-Robert, CFI