How do I directly modify a Google Chrome Extension File CRX

Question

I m not sure in which languages those extensions are  I think the are written in Html  Javascript or JSON  As far as I know they are  compressed  in a  CRX file   It is possible to directly modify the html  js  json of a Chrome Extension  or whatever language they use

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Already said  I found this out while making some Chrome themes  which are long gone now     -P   Chrome themes  extensions  etc  are just compressed files  Get 7-zip or WinRar to unzip it  Each extension theme has a manifest json file  Open the manifest json file in notepad  Then  if you know the coding  modify the code  There will be some other files  If you look in the manifest file you might be able to figure out what the are for  Then  you can change everything

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I searched it in Google and I found this   The Google Chrome Extension file type is CRX  It is essentially a compression format  So  if you want to see what is behind an extension  the scripts and the code  just change the file-type from    CRX    to    ZIP      Unzip the file and you will get all the info you need  This way you can see the guts  learn how to write an extension yourself  or modify it for your own needs  Then you can pack it back up with Chrome   s internal tools which automatically create the file back into CRX  Installing it just requires a click

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It s possible to modify the code of  CRX extension  because it s a simple  zip archive  You can download extension  extract it s source code  modify it  test and debug it as it s on your side   and package back into  CRX file   I googled out this tool to simply download  CRX extension and extract the source code and it worked for me  http   crxextractor com  Everything it does is parses  CRX file format and extracts actual  zip containing the source code

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Now Chrome is multi-user so Extensions should be nested under the OS user profile then the Chrome user profile  My first Chrome user was called Profile 1  my Extensions path was C  Users  username  AppData Local Google Chrome User Data  Profile 1  Extensions    To find yours Navigate to chrome   version   I use about  out of laziness    Notice the Profile Path and just append  Extensions  and you have yours   Hope this brings this info on this question up to date more

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If you have installed the Portable version of Chrome  or have it installed in a custom directory - the extensions won t be available in directory referenced in above answers   Try right-clicking on Chrome s shortcut  amp  Check the  Target  directory  From there  navigate to one directory above and you should be able to see the User Data folder and then can use the answers mentioned above

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Note that some zip programs have trouble unzipping a CRX like sathish described - if this is the case  try using 7-Zip - http   www 7-zip org

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Installed Chrome extension directories are listed below     Copy the folder of the extension you wish to modify    Named according to the extension ID  to find the ID of the extension  go to chrome   extensions    Once copied  you have to remove the  metadata folder    From chrome   extensions in Developer mode select Load unpacked extension    and select your copied extension folder  if it contains a subfolder this is named by the version  select this version folder where there is a manifest file  this file is necessary for Chrome  Make your changes  then select reload and refresh the page for your extension to see your changes      Chrome extension directories  Mac    Users username Library Application Support Google Chrome Default Extensions   Windows 7    C  Users username AppData Local Google Chrome User Data Default Extensions   Windows XP    C  Documents and Settings YourUserName Local Settings Application Data Google Chrome User Data Default   Ubuntu 14 04      config google-chrome Default Extensions

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A signed CRX file has a header that will cause most all unzippers to barf  This is not the easiest way to go about it  but here s how to do it from a bash command line   The basic idea is to find where the original unsigned zipfile begins  then copy the CRX file to a zip file but exclude the CRX header    hexdump -C the extension crx   more Look in the output for the start of the zip file  which are the ASCII bytes  PK   In the sample I tried  the PK was at offset 0x132   From reading the CRX spec  I think this number will vary from file to file because of different signature lengths   That number is what we ll use in the next step  dd if the extension crx of the extension zip bs 1 skip 0x132  For the skip parameter  substitute the offset you found in the previous step   Now unzip the  zip that you just created  Fiddle with the files in the unzipped directory  then either install the unsigned unpacked extension into your Chrome installation  or else repackage it just as you would any other Chrome extension    I m sure that there is a more concise way to do this  Bash experts  please improve on my answer

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I have read the other answers and found it important to note a few other things   1   For Mac users  When you click   Load unpacked extension      the Library folder is by default hidden and  even if the Show Hidden files option is toggled on your Mac  it might not show up in Chrome s finder window    2   The sub folder containing the extension is a random alpha-numeric string named after the extension s ID  which can be found on Chrome s extension page if Developer flag is set to true   Upper right hand checkbox on the extensions page

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CRX files are like  ZIP files  just change the extension and right click   Extract Files and you are done   Once you have extracted files --  modify them and add to zip and change extension back to  crx   Other way around --  Open Chrome --  Settings --  Extensions --  Enable Developer Options --  Load unpacked Extension  modified extracted files folder  and then click pack extension   Source

[google-chrome] How do I directly modify a Google Chrome Extension File? (.CRX)

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