The Botany Bay is an Uncommon Grade 3 Survey ship, and it's built around one job: mining corrupted and decoded data in Augment space. Its mining bonus for Augment data runs around 26,500%, which makes it dramatically more efficient at that specific resource than any other ship in the game. Owning it also unlocks Augment space itself, new missions there, and the Augment Faction Store -- the gateway to Augment officer shards and other faction rewards.
You need 60 blueprints to build the Botany Bay. They come from completing a specific set of missions (Reunions, Buyer's Remorse, Broken Chains, Equal Share, and Quid Pro Quo, picked up in Amador or Midnight), a small Augment Store pack offering 12 extra blueprints for players who haven't built it yet, and the Ascension research tree. Once built, it upgrades on Common, Uncommon, and Rare Plutonium, which boosts cargo capacity and cargo protection. It stays relevant well past the early game -- the arrival of the Independent Archives content kept the Botany Bay in the mining rotation rather than retiring it.