User can click “Report dead link” — the portable app stores the failure event. When back online, it anonymously contributes to a shared dead-link DB. Later, if any user finds a working link for that hash, the fix is pushed to others via a tiny P2P-like update (no central server required — using BitTorrent DHT or IPFS).
Here’s an interesting feature idea for a hypothetical tool — designed as a lightweight, offline-first utility for movie enthusiasts and downloaders who frequently encounter dead or broken links. 404 filmyzilla portable