Examine source code of summifyAllTables

{
  "manifest_version": 2,
  "name": "summifyAllTables",
  "description": "Click to insert a row to any tables with that column's sum.",
  "version": "0.1.0",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "512": "summifyAllTables.png"
    }
  },
  "background": {
    "persistent": false,
    "scripts": [
      "summifyAllTables.js"
    ]
  }
}