Examine source code of Which Salary LinkedIn ?

{
  "description": "Adds new button for canned answers on LinkedIn",
  "manifest_version": 2,
  "name": "Which Salary ?",
  "version": "1.0",
  "homepage_url": "https://github.com/GiovanniSM20/linkedin-which-salary",
  "content_scripts": [
    {
      "matches": [
        "*://*.mozilla.org/*"
      ],
      "js": [
        "which-salary.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{684f2218-e5b2-4d3d-ab3f-cc84133697d5}"
    }
  }
}