Like how they use this <d ref="Effect,SeekerMissileDamage,Amount"/> for the raven seeker missile damage.

I guess it's pretty simple.

<d ref="data type,data name,field name" />

Now, I don't have the Data Editor next to me. You will maybe need to put the Data Editor into "Display Raw Values" mode. It's one of the 6 buttons at the top-center of the Data Editor window.

<d ref="Unit,Marine,Movespeed"/> should return 2.25 or whatever the value is.
<d ref="Ability,Blink,Cooldown"/> should return 8 or whatever the value is.
<d ref="Effect,LongboltMissilePersistent,Period"/> should return 2.

Again, I don't have access to the data editor, but judging by your post - that is how it operates.

I get it know, thanks alot.