# 34 12 AA 55 — File format magic numbers

For 34 12 AA 55, offset is 0; extension is vpk; format is VPK file, used to store game data for some Source Engine games, recorded from its source on 2026-08-03.

- **Hex signature:** 34 12 AA 55 _(unconfirmed — we could not tie this to the quote below)_
- **Offset:** 0 _(unconfirmed — we could not tie this to the quote below)_
- **Extension:** vpk
- **Format:** VPK file, used to store game data for some Source Engine games

## What the source says

> VPK file, used to store game data for some <https://en.wikipedia.org/wiki/Source_Engine> Source Engine games

## Source

- https://en.wikipedia.org/wiki/List_of_file_signatures

Last verified: 2026-08-03. Review by: 2027-08-03.
Part of [File format magic numbers](https://referencesource.org/file-format-signatures/).