Examine source code of Furiganaize

{
  "name": "__MSG_manifestExtName__",
  "version": "0.7.2",
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "{a2503cd4-4083-4c2f-bef2-37767a569867}"
    }
  },
  "background": {
    "scripts": [
      "common.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "kanji_content_detect.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*",
        "file://*/*"
      ],
      "all_frames": true
    }
  ],
  "default_locale": "en",
  "description": "__MSG_manifestExtDescription__",
  "icons": {
    "512": "img/icon_black.svg"
  },
  "options_ui": {
    "page": "user_cp/options.html",
    "browser_style": true,
    "open_in_tab": false
  },
  "browser_action": {
    "default_title": "Toggle furigana",
    "default_icon": {
      "512": "img/icon_mobile.svg"
    },
    "theme_icons": [
      {
        "light": "img/icon_light.svg",
        "dark": "img/icon_dark.svg",
        "size": 48
      }
    ]
  },
  "commands": {
    "toggle-furigana": {
      "suggested_key": {
        "default": "Ctrl+Shift+F",
        "mac": "Command+Shift+F",
        "android": "Ctrl+Shift+F"
      },
      "description": "Toggle furigana"
    }
  },
  "permissions": [
    "http://*/*",
    "https://*/*",
    "file://*/*",
    "<all_urls>",
    "activeTab",
    "tabs",
    "storage"
  ]
}