Sumer

manifest.json

{
  "manifest_version": 2,
  "name": "Sumer",
  "description": "Get a total duration by selecting a region with a list of durations",
  "version": "1.6",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": {
      "38": "icon256.png"
    },
    "default_title": "Calculate total duration"
  },
  "icons": {
    "256": "icon256.png"
  }
}