Firebug and cURL
Solution 1:
It's not encrypted, it's compressed. In your request, you send "Accept-Encoding: gzip, deflate" so the server is compressing the response for optimization.
You need to remove the -H "Accept-Encoding: gzip, deflate" and you should see the normal response.
OR
You can install gunzip if not already installed and pipe your curl command as curl [...] | gunzip -.