What is a .PACK file?
PACK is the compressed bundle git uses to store many repository objects together, delta-compressed against one another, under .git/objects/pack. Created and read by git.
- Did you know
- When you clone or fetch, git transfers history as a single packfile rather than thousands of loose objects, then keeps it paired with a .idx index for fast lookup.
- Git shrinks a pack by storing many objects as deltas - just the difference from a similar object - so a long file history can take barely more room than a single copy.
- Running git gc rewrites loose objects and older packs into one freshly, tightly compressed packfile.
- A packfile ends with a 20-byte SHA-1 checksum of everything before it, so git can tell whether the bundle was corrupted in transit.
- What Analyser shows you
- Open git repository internals with no git binary: loose objects (the zlib-compressed blob, tree, commit and tag files under .git/objects), pack files (.pack) and pack indexes (.idx). Inflates and parses each object - showing its type, size and SHA-1, rendering commit and tag messages, listing tree entries, and handing blob contents to the analyser.
- Open a .PACK file
- Drag a .PACK file onto the Analyser home page (or tap to pick one). It opens entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.
- Related formats
- .IDX. See all supported file types.