Where is gating.yaml fetched from? How does the branch relate to product_versions?

[Miro Hrončok]

I wonder, if gating.yaml has this section:

product_versions:
   - fedora-*

Where is gating.yaml actually taken from? Is it the branch that is being gated, 
or always master, or something else?

Why is the "product_version" not determined by the branch?

Thanks for clarifying.