{
 "id": "chm",
 "name": "CHM",
 "category": "other",
 "identifiers": {
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   "chm",
   "chw"
  ],
  "mime": [
   "application/vnd.ms-htmlhelp"
  ],
  "puid": [
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  "wikidata": [
   "Q1023647"
  ],
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    "hex": "4954534603000000",
    "notes": "File Formats Wiki"
   },
   {
    "offset": 0,
    "hex": "49545346",
    "notes": "Microsoft Compiled Help file"
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    "name": "Microsoft Compiled Help file",
    "sequences": [
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      "pattern": "49545346"
     }
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  ]
 },
 "status": "readable",
 "summary": "This is an outline record only, and requires further details, research or authentication to provide information that will enable users to further understand the format and to assess digital preservation risks associated with it if appropriate. If you are able to help by supplying any additional information concerning this entry, please return to the main PRONOM page and select ‘Add an Entry’.",
 "tools": [
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   "url": "http://www.adobe.com/products/robohelp/",
   "reads": false,
   "writes": true
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   "name": "Apache Tika",
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   "reads": true,
   "writes": false,
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   "name": "B1 Free Archiver",
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   "writes": false,
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  {
   "name": "chmlib",
   "url": "http://www.jedrea.com/chmlib/",
   "reads": true,
   "writes": false,
   "license": "GNU Lesser General Public License, version 2.1",
   "open_source": true
  },
  {
   "name": "Chmox",
   "url": "https://chmox.sourceforge.net/",
   "reads": true,
   "writes": false
  },
  {
   "name": "ExifTool",
   "url": "https://exiftool.org/",
   "reads": true,
   "writes": false,
   "license": "Artistic License / GNU General Public License, version 1.0 or later",
   "open_source": true
  },
  {
   "name": "GnoCHM",
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   "reads": true,
   "writes": false
  },
  {
   "name": "ICE Book Reader",
   "url": "https://ice-graphics.com/ICEReader/IndexE.html",
   "reads": true,
   "writes": false
  },
  {
   "name": "KCHM",
   "url": "https://www.wikidata.org/wiki/Q124728550",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License, version 2.0",
   "open_source": true
  },
  {
   "name": "libmspack",
   "url": "https://www.cabextract.org.uk/libmspack/",
   "reads": true,
   "writes": false,
   "license": "GNU Library General Public License, version 2.0",
   "open_source": true
  },
  {
   "name": "Okular",
   "url": "https://okular.kde.org",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License, version 2.0",
   "open_source": true
  },
  {
   "name": "PhotoRec",
   "url": "http://www.cgsecurity.org/wiki/PhotoRec",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License",
   "open_source": true
  },
  {
   "name": "Q215051",
   "url": "https://7-zip.org",
   "reads": true,
   "writes": false,
   "license": "GNU Lesser General Public License",
   "open_source": true
  },
  {
   "name": "Q479808",
   "url": "https://www.sumatrapdfreader.org",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License, version 3.0",
   "open_source": true
  },
  {
   "name": "Q62853075",
   "url": "https://www.ulduzsoft.com/linux/kchmviewer/",
   "reads": true,
   "writes": false
  },
  {
   "name": "xCHM",
   "url": "https://www.wikidata.org/wiki/Q8041710",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License",
   "open_source": true
  },
  {
   "name": "Zipeg",
   "url": "http://www.zipeg.com/",
   "reads": true,
   "writes": false,
   "license": "BSD licenses",
   "open_source": true
  }
 ],
 "projects": [
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   "name": "File Formats Wiki",
   "url": "http://fileformats.archiveteam.org/wiki/CHM",
   "kind": "wiki"
  },
  {
   "name": "PRONOM fmt/634",
   "url": "https://www.nationalarchives.gov.uk/PRONOM/fmt/634",
   "kind": "format-doc"
  },
  {
   "name": "Wikidata Q1023647",
   "url": "https://www.wikidata.org/wiki/Q1023647",
   "kind": "wiki"
  }
 ],
 "provenance": {
  "sources": [
   "ffw",
   "pronom",
   "wikidata"
  ]
 },
 "updated": "2026-10-24",
 "aliases": [],
 "structure": [],
 "parsers": [],
 "conversions": [],
 "samples": [],
 "claims": [],
 "verification": []
}