Feed Rules allow you to edit and customize select feed attributes for all your channels by building rules that alter your product details.
Any rules you build will function in perpetuity so that anytime new products are added to your feed, and as long as they match your rule criteria, they will also be updated and sent to your channels.
The editable fields are as follows:
Additional Image Links
Ads Redirect URL
Age Group
Availability
Brand
Color
Condition
Custom Labels 0-4
Description
Gender
GTIN
ID
Identifier Exists
Image Link
Is Bundle
Item Group ID
Link
MPN
Material
Multi-Pack
Patten
Product Type
Promotion ID
Sale Price
Shipping
Shipping Dimensions: Height, Length Width
Shipping Label
Sizes
Title
Exclude From Channel
Include In Channel
Refer to https://support.google.com/merchants/answer/7052112?hl=en for a detailed overview of each attribute.
The fields Included Destination, Sell On Google Price & Sell On Google Sale Price can be available upon the addition of the Buy On Google channel to your plan.