Examine source code of DigProxy PoliTO

{
  "manifest_version": 2,
  "name": "DigProxy service by Politecnico di Torino",
  "version": "1.0",
  "description": "Four-line-code extension that allows to open (into a new tab) the active website using the proxy service (ezproxy.biblio.polito.it) offered by the library of Politecnico di Torino.",
  "browser_action": {
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs"
  ]
}