Tiered link building helps boost your site’s authority by creating two levels...

https://seo.edu.rs/blog/how-do-i-build-tier-2-content-that-looks-natural-and-not-forced-11162

Tiered link building helps boost your site’s authority by creating two levels of backlinks. Tier 1 links point directly to your website from quality sources, while Tier 2 links support those Tier 1 links, making them stronger