Tiered link building uses two levels of backlinks to boost your site's...

https://scarlettsuniquedigest.yousher.com/broken-link-building-step-by-step-using-ahrefs

Tiered link building uses two levels of backlinks to boost your site's authority. Tier 1 links point directly to your site, giving it real value. Tier 2 links support those Tier 1 links, making them stronger and more effective