Mapping to a ZIP Archive

This Open Packaging specification defines a mapping for the ZIP archive format. Future versions of this Open Packaging specification might provide additional mappings.

A ZIP archive is a ZIP file as defined in the ZIP file format specification excluding all elements of that specification related to encryption, decryption, or digital signatures. A ZIP archive contains ZIP items.

Note: :ZIP items become files when the archive is unzipped. When users unzip a ZIP-based package, they see a set of files and folders that reflects the parts in the package and their hierarchical naming structure.

Table 9–2, Package model components and their physical representations, shows the various components of the package model and their corresponding physical representation in a ZIP archive.

Table 1. 9–2. Package model components and their physical representations
Package model component	Physical representation
Package	ZIP archive file
Part	ZIP item
Part name	Stored in item header (and ZIP central directory as appropriate). See §9.2.3 for conversion rules.
Part content type	ZIP item containing XML that identifies the content types for each part according to the pattern described in §9.1.2.1.
Growth hint	Padding reserved in the ZIP Extra field in the local header that precedes the item. See §9.2.7 for a detailed description of the data structure.