Examine source code of Monochromer

{
  "manifest_version": 2,
  "name": "Monochromer",
  "version": "0.3.1resigned1",
  "description": "This extension makes web site monochrome.",
  "author": "xia@silvia.com",
  "homepage_url": "https://github.com/xia-sava/monochromer",
  "applications": {
    "gecko": {
      "id": "{ae06def4-e82b-4894-b4ea-cb7f9090f2aa}"
    }
  },
  "permissions": [
    "activeTab"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "icons": {
    "512": "icons/monochromer.svg"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "512": "icons/monochromer.svg"
    },
    "default_title": "Monochrome this page"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/content.js"
      ]
    }
  ]
}