Examine source code of Mi-SigNature

{
  "name": "Mi-SigNature",
  "version": "0.0.3resigned1",
  "minimum_chrome_version": "40.0",
  "manifest_version": 2,
  "description": "MIMOS SigNature Extension. Use your digital certificate to perform digital signature on web browser",
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*",
        "file:///*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "nativeMessaging"
  ],
  "applications": {
    "gecko": {
      "id": "{f72d1ef1-4d13-4279-90c5-075cc0c4e355}"
    }
  }
}