Examine source code of Reading habits

{
  "manifest_version": 2,
  "name": "Reading habits",
  "version": "0.2.1resigned1",
  "description": "A simple reading habits extension",
  "homepage_url": "https://github.com/diogoalves/webextension-readinghabits",
  "applications": {
    "gecko": {
      "id": "{0db2b632-f7b0-4d50-92a5-4ec55263053b}"
    }
  },
  "icons": {
    "48": "icons/empty-48.png",
    "96": "icons/empty-96.png"
  },
  "permissions": [
    "bookmarks",
    "tabs"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/empty-38.png",
    "default_title": "Reading habits",
    "default_popup": "app.html"
  },
  "background": {
    "scripts": [
      "dist/background.js"
    ]
  }
}