Examine source code of Tab Flipper Plus

{
  "name": "Tab Flipper Plus",
  "description": "Press Ctrl+Shift+Right or Ctrl+Shift+Left (Command+Shift+Right or Command+Shift+Left on a Mac) to flip through window tabs",
  "version": "3.2",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "images/tabFlipper16.png",
    "default_title": "Press Ctrl(Win)/Command(Mac)+Shift+ Left or Right to Flip Tabs"
  },
  "commands": {
    "flip-tabs-forward": {
      "suggested_key": {
        "default": "Ctrl+Shift+Right",
        "mac": "Command+Shift+Right"
      },
      "description": "Flip tabs forward"
    },
    "flip-tabs-backwards": {
      "suggested_key": {
        "default": "Ctrl+Shift+Left",
        "mac": "Command+Shift+Left"
      },
      "description": "Flip tabs backwards"
    }
  },
  "icons": {
    "16": "images/tabFlipper16.png",
    "32": "images/tabFlipper32.png",
    "48": "images/tabFlipper48.png",
    "128": "images/tabFlipper128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4afc5a58-7536-4cdf-b382-f04249c78fc7}"
    }
  }
}