Please define your internal slot notation before using it

[bzbarsky]

https://w3c.github.io/browser-payment-api/#constructor step 15 says:

Store methodData into request@[[methodData]].

I assume this means "store methodData into the internal slot of request that is named [[methodData]]". But nothing in this document (certainly nothing before this point) actually defines that that's what the '@' notation means.

[bzbarsky]

Ah, I see, it's hiding all the way in the end in section 18. This sort of definition should be at the beginning of the document, or the '@' needs to link to its definition. Or both.