A historical Google system introduced in 2012 to combat link spam and incorporated into core ranking systems in 2016.
Older link audits may describe a site as affected by Penguin. The term refers to algorithmic handling of manipulative links, not automatically to a manual action. Those are different mechanisms, and a manual action has its own Search Console evidence and review process.
Link quality cannot be reduced to a single third-party score. Look at why the link exists, how it was obtained and whether it is intended to manipulate rankings. A relevant editorial reference differs from a paid network placement sold primarily to pass ranking credit.
For an existing business, begin with the actual acquisition history and current evidence. Do not disavow or remove every unfamiliar link merely because a tool marks it red. A historical label alone does not prove that a particular incoming link is causing a loss.
Takeaway: Build references that make sense for real audiences and investigate manipulative link practices with evidence, not fear-based automated scores.
Example
A business discovers that an earlier supplier bought hundreds of network placements. It documents the arrangement and reviews applicable spam guidance instead of replacing them with another package promising a higher authority score.
What to check
Check Search Console for a manual action separately. Keep corrective actions proportionate to documented link practices.
For more detail, see Google Search ranking systems guide.