Question 1

What is a XAR file?

Accepted Answer

XAR (eXtensible Archive Resource) is Apple's archive format introduced in Mac OS X 10.4. It starts with the magic 'xar!' (0x78 0x61 0x72 0x21), followed by a 28-byte header containing offsets to a compressed XML Table of Contents, and a heap of compressed file data. XAR is used for macOS installer packages (.pkg) and Software Update payloads.

Question 2

How does this extractor work?

Accepted Answer

We read the 28-byte XAR header to find the compressed TOC (always zlib-deflated), decompress it with the browser's built-in DecompressionStream, parse the resulting XML, and walk the <toc> tree to build a list of files with their offsets into the heap. Each file may be individually zlib-compressed; we decompress on demand when you click Download.

Question 3

Can this tool fully extract every XAR file?

Accepted Answer

Yes for files using zlib (the most common compression). XAR also supports bzip2, gzip, and LZMA per-file encodings — we support zlib and stored (no compression); other methods surface a clear 'unsupported compression' error. Encrypted XAR payloads (rare) are not supported.

Question 4

What is the XML TOC?

Accepted Answer

The Table of Contents is a zlib-compressed XML document that lists every file in the archive with its name, size, type (file/dir/symlink), encoding, and offset into the heap. We render the raw XML in a viewer so you can inspect the structure of any XAR file.

Question 5

What extra features does this tool have compared to others?

Accepted Answer

10 extras: (1) Drag-drop input. (2) File tree with directories expanded. (3) Search filter by name. (4) Type filter (all / files / dirs / symlinks). (5) Stats panel (file count, total uncompressed, compression ratio, encoding breakdown). (6) Download individual files. (7) Download all as a new ZIP archive. (8) Raw XML TOC viewer. (9) History of recently opened .xar files (localStorage — last 10). (10) Shareable URL with current view settings.

Question 6

Is my .xar file uploaded anywhere?

Accepted Answer

No. All XAR parsing, zlib decompression, and ZIP repackaging happens in your browser using native APIs. File contents never leave your device. Only filenames and counts are saved to local history.

XAR Extractor

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