Life leech damage

I’m not clear on life leech. if it says +20% life leech damage does that mean ANY lifetap (SoC, Bloodthirst, or % damage converted to health on a weapon for example) gets whatever health is returned to you buffed by 20%?

Or does it just mean “life leech damage” is buffed; as i believe there are devotions and abilities on gear that specifically state 150 life leech damage or some such.

It’s specifically for the life leech DoT stat, such as what you find on some devotions and skills.