Examine source code of bebop

{
  "name": "bebop",
  "version": "0.2.2",
  "manifest_version": 2,
  "description": "Offer emacs key-bindings and command line interface like helm",
  "author": "Hiroki Kumamoto",
  "applications": {
    "gecko": {
      "id": "bebop@kumabook",
      "strict_min_version": "45.0"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "64": "icons/icon-64.png"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "history",
    "bookmarks",
    "storage",
    "cookies",
    "sessions",
    "system.display",
    "search",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background/bundle.js"
    ]
  },
  "default_locale": "en",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_scripts/bundle.js"
      ],
      "run_at": "document_start",
      "match_about_blank": true
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "64": "icons/icon-64.png"
    },
    "theme_icons": [
      {
        "light": "icons/icon-dark-16.png",
        "dark": "icons/icon-16.png",
        "size": 16
      },
      {
        "light": "icons/icon-dark-32.png",
        "dark": "icons/icon-32.png",
        "size": 32
      },
      {
        "light": "icons/icon-dark-64.png",
        "dark": "icons/icon-64.png",
        "size": 64
      }
    ],
    "default_title": "button label",
    "default_popup": "popup/index.html"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Comma",
        "mac": "MacCtrl+Comma",
        "linux": "Ctrl+Comma"
      }
    },
    "toggle_popup_window": {
      "description": "Toggle popup window"
    },
    "toggle_content_popup": {
      "description": "Toggle popup in current content"
    }
  },
  "options_ui": {
    "page": "options_ui/index.html"
  },
  "web_accessible_resources": [
    "images/*.png",
    "popup/*"
  ]
}