Trust Flow, a trademark of Majestic, is a score based on quality, on a scale between 0-100. Majestic collated many trusted seed sites based on a manual review of the web. This process forms the foundation of Majestic Trust Flow. Sites closely linked to a trusted seed site can see higher scores, whereas sites that may have some questionable links would see a much lower score.
This data is available within gShift on the Backlink Summary page.