How does Gorefeast work?

Just to clarify, does the ‘15% Chance for x% Bleeding Damage’ apply to all sources of Bleed, for example, Devouring Swarm or is just to weapon attacks/skills with % WD?

Im not really sure but i suppose for any kind of your attacks would have 15% to activate extra x% bleed dmg?

afaik basically any time you would deal bleeding damage, there’s a 15% chance for it to have the modifier applied.

This is correct.

Conversely, 15% Chance of <Flat> Bleeding Damage applies only through % Weapon Damage and will be modified by that % WD accordingly. But % of % chance is global and can proc from anywhere.