Tiered link building boosts your website’s authority by using multiple layers...

https://highstylife.com/how-do-i-tell-if-a-backlink-is-relevant-or-just-high-da-fluff/

Tiered link building boosts your website’s authority by using multiple layers of backlinks. Tier 1 links point directly to your site, while Tier 2 links support those Tier 1 sources