“Google has long taken a strong stance against links that manipulate a site’s PageRank.
Today we would like to reiterate our policy on the creation of keyword-rich, hidden or low-quality links embedded in widgets that are distributed across various sites.
Google’s webspam team may take manual actions on unnatural links. When a manual action is taken, Google will notify the site owners through Search Console.
If you receive such a warning for unnatural links to your site and you use links in widgets to promote your site, we recommend resolving these issues and requesting reconsideration.”