A Redirect Chain is a series of redirects between the initial URL and the destination URL. Here is an example:
This referring page to ahrefs.com redirects twice before reaching its final destination https://ahrefs.com/blog/find-competitors-backlinks.
How to find redirect chains in Site Explorer
Any report that refers to link-related data has the option to filter for redirect chains. This includes Backlinks, Broken backlinks, Outgoing links, and Calendar reports. Here's how it works:
Click on + More filters
In the Target Page section, click on No. of redirects
Then, select Redirect chain and click Show results.
You will see the results populated only with target links having redirect chains:
How to find redirect chains in Site Audit
First you would need to crawl a website in Site Audit.
Then, if pages in the website has redirect chains, it will be flagged in the "Redirect chain" issue under the Redirects section.
How to check for redirect chains using the SEO Toolbar
If you have the Ahrefs SEO Toolbar installed, you can click on any link and wait for the destination page to load.
Then click on the extension icon, and click on the HTTP headers tab to see any redirects that may have happened: