Examine source code of Reddit Karma Blocker

{
  "manifest_version": 2,
  "name": "Reddit Karma Blocker",
  "author": "Erlend Eelmets",
  "version": "1.4",
  "description": "Blocks Karma numbers in reddit. ",
  "icons": {
    "144": "icons/new/144.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_icon": {
      "144": "icons/new/144.png"
    },
    "default_title": "Reddit Karma Blocker",
    "default_popup": "popup/popup.html"
  },
  "options_ui": {
    "page": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.reddit.com/*"
      ],
      "js": [
        "content-script.js"
      ],
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{680366a5-a9c9-4faf-8431-be6087427d38}"
    }
  },
  "web_accessible_resources": [
    "icons/new/128.png",
    "icons/new/144.png"
  ]
}