Examine source code of ResizeIT 2

{
  "manifest_version": 2,
  "name": "ResizeIT 2",
  "description": "Restore one of four preset window sizes + positions",
  "version": "2.2.0",
  "icons": {
    "48": "logo.png",
    "96": "logo@2x.png"
  },
  "background": {
    "scripts": [
      "options/common.js",
      "main.js"
    ]
  },
  "commands": {
    "preset-1": {
      "suggested_key": {
        "default": "Alt+1",
        "mac": "MacCtrl+1",
        "linux": "Ctrl+1"
      },
      "description": "Switch to preset 1"
    },
    "preset-2": {
      "suggested_key": {
        "default": "Alt+2",
        "mac": "MacCtrl+2",
        "linux": "Ctrl+2"
      },
      "description": "Switch to preset 2"
    },
    "preset-3": {
      "suggested_key": {
        "default": "Alt+3",
        "mac": "MacCtrl+3",
        "linux": "Ctrl+3"
      },
      "description": "Switch to preset 3"
    },
    "preset-4": {
      "suggested_key": {
        "default": "Alt+4",
        "mac": "MacCtrl+4",
        "linux": "Ctrl+4"
      },
      "description": "Switch to preset 4"
    }
  },
  "permissions": [
    "storage"
  ],
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "browser_action/icon-dark.png",
      "32": "browser_action/icon-dark@2x.png"
    },
    "default_title": "ResizeIT 2",
    "default_popup": "browser_action/popup.html",
    "theme_icons": [
      {
        "dark": "browser_action/icon-dark.png",
        "light": "browser_action/icon-light.png",
        "size": 16
      },
      {
        "dark": "browser_action/icon-dark@2x.png",
        "light": "browser_action/icon-light@2x.png",
        "size": 32
      }
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "resizeit-2@futuretech.in"
    }
  }
}