The EU Council Directive 2001/110/EC of 20 December 2001 relating to honey, in Annex I, there is a list of honey types. Among them are (the emphasis is mine):
(iii) comb honey
Honey stored by bees in the cells of freshly built broodless combs or thin comb foundation sheets made solely of beeswax and sold in sealed whole combs or sections of such combs;
(iv) chunk honey or cut comb in honey
Honey which contains one or more pieces of comb honey;
(v) drained honey
Honey obtained by draining decapped broodless combs;
(vi) extracted honey
Honey obtained by centrifuging decapped broodless combs;
(vii) pressed honey
Honey obtained by pressing broodless combs with or without the application of moderate heat not exceeding 45 °C;
I have been told before that this means comb that has never been used for brood, but it's not formally defined in the regulation so I've sent off an email to our local Dept. of Agriculture to see if they can provide an answer.
Personally, I never use comb that has held brood for extraction, perhaps because I'm a bit fussy and would be concerned about contaminants. However, I'll happily feed it to the bees, and I have no doubt that much of it ends up in the pristine supers.
I don't know if this particular piece regulation has been incorporated into post-Brexit requirements in the UK, but I imagine there's something similar.