DeadLinkAlertBot

User agent: DeadLinkAlertBot/1.0 (+https://deadlinkalert.com/bot)

It visits a site only when that site's owner (or someone who pasted its address) asks for a broken-link scan, plus scheduled re-scans. It fetches one page at a time with a pause between requests, follows robots.txt (Disallow and Crawl-delay), stays on the site's own domain, stops at a page cap, and only sends HEAD/GET requests to outbound links to check they work.

To block it, add User-agent: DeadLinkAlertBot / Disallow: / to your robots.txt.