Examine source code of Link Visitor

{
  "manifest_version": 2,
  "name": "Link Visitor",
  "default_locale": "en_US",
  "version": "5.4resigned1",
  "author": "Kevin Milburn",
  "description": "Mark link(s) as visited or unvisited",
  "developer": {
    "name": "Kevin Milburn",
    "url": "https://github.com/kinitawowi/linkvisitor-firefox"
  },
  "applications": {
    "gecko": {
      "id": "{9C013B6E-46FC-11DD-B644-FC4D56D89593}",
      "strict_min_version": "52.0"
    }
  },
  "background": {
    "scripts": [
      "background/weh-core.js",
      "common/weh-prefs.js",
      "common/weh-i18n.js",
      "background/weh-inspect.js",
      "background/weh-bg-prefs.js",
      "background/weh-ui.js",
      "background/weh-ajax.js",
      "background/weh-i18n-keys.js",
      "background/default-prefs.js",
      "background/background.js"
    ],
    "persistent": true
  },
  "icons": {
    "32": "content/images/icon-32.png",
    "40": "content/images/icon-40.png",
    "48": "content/images/icon-48.png",
    "64": "content/images/icon-64.png",
    "128": "content/images/icon-128.png"
  },
  "browser_action": {
    "default_icon": {
      "40": "content/images/icon-40.png"
    },
    "default_title": "Mark Links Un/Visited",
    "default_popup": "content/popup.html",
    "browser_style": true
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "content/main.js"
      ],
      "css": [
        "content/styles.css"
      ]
    }
  ],
  "options_ui": {
    "page": "content/settings.html?panel=preferences",
    "browser_style": true
  },
  "commands": {
    "linkvisitor-markall-visited": {
      "suggested_key": {
        "default": "Ctrl+Shift+1"
      },
      "description": "Mark all links of the page as visited"
    },
    "linkvisitor-markall-unvisited": {
      "suggested_key": {
        "default": "Ctrl+Shift+2"
      },
      "description": "Mark all links of the page as unvisited"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "contextMenus",
    "history",
    "bookmarks",
    "<all_urls>",
    "storage"
  ]
}