Examine source code of Erasmus

{
  "manifest_version": 2,
  "name": "Erasmus",
  "version": "1.0",
  "description": "Reader view addon that does more than clean up web pages for better reading: Highlights key phrases in a text, and provide links to Wikipedia articles and Google searches of these phrases.",
  "homepage_url": "https://geterasmus.com/",
  "icons": {
    "16": "icons/letter-e-16.png",
    "24": "icons/letter-e-24.png",
    "32": "icons/letter-e-32.png",
    "48": "icons/letter-e-48.png",
    "64": "icons/letter-e-64.png",
    "128": "icons/letter-e-128.png",
    "256": "icons/letter-e-256.png",
    "512": "icons/letter-e-512.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/letter-e-48.png",
    "default_title": "Erasmus"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "Readability.js",
        "content_script.js"
      ]
    }
  ]
}