[HelenePhisher]

You can extract the .crx without Javascript using this webservice: http://crxextractor.com/

Used it a couple of times in the past, it is a good one.

[Zren]

All you need to do is remove the first 306 bytes to turn it into a normal zip file.

    tail -c +307 in.crx > out.zip

Credit to this guy in the comments. https://superuser.com/questions/139190/how-to-unpack-a-chrom...