Angelic Buster's link skill

Angelic Buster's link skill, terms and conditions, at lv2 it gives 45% skill damage.
What does skill damage mean? Is it 45% more total damage% upon using skills or every hit of skills has 45 more percentage point (E.g. 340% per hit to 385% per hit) or something else?

Thanks!

Fairly certain it's just %total damage, idk why they listed it as skill damage.

Fairly certain it's just %total damage, idk why they listed it as skill damage.

I see. Thank you!