While "Thief-Complete-Edition.rar" specifically refers to a compressed archive file often found on file-sharing or third-party sites, the (also known as the Definitive Edition on some platforms) is the official way to experience the full content of the 2014 reboot.
Below is a blog post layout covering the game's features, what is included in the complete package, and how to access it safely.
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The "Master Thief" or Definitive Edition typically bundles the base game with all released digital extras and gameplay expansions: