Inbox Preview's Content Assessment feature provides information on redirected links that can be affecting reputation and deliverability if they are spammy, suspected of phishing or more.
Mailbox providers check if a link in the body of an email is listed on a URL blocklist or has a high rate of complaints from its users. If a URL is deemed spam-like, mailbox providers may block or route the mail to the spam, bulk, or junk folder. Mailbox providers are also evaluating the landing page that a URL redirect resolves to.
Inbox Preview's Content Assessment feature uses Link Check, powered by the Google Safe Browsing API, to check the links in your test emails against Google's updated list of suspected phishing, malware, and unwanted software pages.