This is a resolver, not a document. It maps a severed Zenodo DOI to its record in this archive. Resolution runs in the browser against /api/doi-axn-map.json, so an automated checker that does not execute scripts sees this page rather than the target.
Link checkers: a 200 on this URL means the resolver is reachable. It does not verify the target. Verification requires the map lookup below.
To resolve without scripts: open the map above and look up the DOI in this page's ?doi= parameter. The entry gives the work's AXN identifier and the URL of its record page. The full index of severed DOIs, with status and successor, is at /data/doi-resolution-index.json. Or use the resolver info page.