Overview
A proto-persona is the technical term for a persona created solely on the assumptions of the product team.
These personas are lightweight, can be rapidly written up, and serves as a jumping-off point for later user research, assumptions validations, etc.
They are not replacements, rather supplements, for proper persona documents.
A good proto-persona exercise should still contain all the components of a regular persona: Identity, Segmentation, Demographics, Environments, Needs, Goals, and Pain Points.
Product managers may use method in early-stage development to consolidate early assumptions about potential users.