NAME

       gitformat-bundle - The bundle file format

SYNOPSIS

       *.bundle
       *.bdl

DESCRIPTION

       The Git bundle format is a format that represents both refs and Git objects. A bundle is a header in a
       format similar to git-show-ref(1) followed by a pack in *.pack format.

       The format is created and read by the git-bundle(1) command, and supported by e.g. git-fetch(1) and git-
       clone(1).

FORMAT

       We will use ABNF notation to define the Git bundle format. See gitprotocol-common(5) for the details.

       A v2 bundle looks like this:

           bundle    = signature *prerequisite *reference LF pack
           signature = "# v2 git bundle" LF

           prerequisite = "-" obj-id SP comment LF
           comment      = *CHAR
           reference    = obj-id SP refname LF

           pack         = ... ; packfile

       A v3 bundle looks like this:

           bundle    = signature *capability *prerequisite *reference LF pack
           signature = "# v3 git bundle" LF

           capability   = "@" key ["=" value] LF
           prerequisite = "-" obj-id SP comment LF
           comment      = *CHAR
           reference    = obj-id SP refname LF
           key          = 1*(ALPHA / DIGIT / "-")
           value        = *(%01-09 / %0b-FF)

           pack         = ... ; packfile

SEMANTICS

       A Git bundle consists of several parts.

       •   "Capabilities", which are only in the v3 format, indicate functionality that the bundle requires to
           be read properly.

       •   "Prerequisites" list the objects that are NOT included in the bundle and the reader of the bundle
           MUST already have, in order to use the data in the bundle. The objects stored in the bundle may refer
           to prerequisite objects and anything reachable from them (e.g. a tree object in the bundle can
           reference a blob that is reachable from a prerequisite) and/or expressed as a delta against
           prerequisite objects.

       •   "References" record the tips of the history graph, iow, what the reader of the bundle CAN "git fetch"
           from it.

       •   "Pack" is the pack data stream "git fetch" would send, if you fetch from a repository that has the
           references recorded in the "References" above into a repository that has references pointing at the
           objects listed in "Prerequisites" above.

       In the bundle format, there can be a comment following a prerequisite obj-id. This is a comment and it
       has no specific meaning. The writer of the bundle MAY put any string here. The reader of the bundle MUST
       ignore the comment.

   Note on shallow clones and Git bundles
       Note that the prerequisites do not represent a shallow-clone boundary. The semantics of the prerequisites
       and the shallow-clone boundaries are different, and the Git bundle v2 format cannot represent a shallow
       clone repository.

CAPABILITIES

       Because there is no opportunity for negotiation, unknown capabilities cause git bundle to abort.

       •   object-format specifies the hash algorithm in use, and can take the same values as the
           extensions.objectFormat configuration value.

       •   filter specifies an object filter as in the --filter option in git-rev-list(1). The resulting
           pack-file must be marked as a .promisor pack-file after it is unbundled.

GIT

       Part of the git(1) suite

Git 2.43.0                                         07/02/2025                                GITFORMAT-BUNDLE(5)