How CRX Downloader works?
Following is the way to download chrome extensions with crx-downloader.com :
1- Enter chrome extension's webstore link in address bar on the site.

2- The click Downlaod button.

3- This will take few seconds and download crx file.

4- Just rename the .crx file to .zip and open it with any zip opener software like WinRAR to check what's in it.