Examine source code of BallastCleaner

{
  "manifest_version": 2,
  "name": "BallastCleaner",
  "version": "1.9",
  "applications": {
    "gecko": {
      "id": "ballastcleaner@tpsoft.org"
    }
  },
  "description": "Removing ballast from websites",
  "icons": {
    "48": "images/ballastcleaner-48.png",
    "96": "images/ballastcleaner-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.hnonline.sk/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/hnonline.sk.js"
      ]
    },
    {
      "matches": [
        "*://*.titulky.com/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/titulky.com.js"
      ]
    },
    {
      "matches": [
        "*://*.sme.sk/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/sme.sk.js"
      ]
    },
    {
      "matches": [
        "*://slovnik.aktuality.sk/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/slovnik.aktuality.sk.js"
      ]
    },
    {
      "matches": [
        "*://*.aktuality.sk/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/_.aktuality.sk.js"
      ]
    },
    {
      "matches": [
        "*://*.hlavnespravy.sk/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/hlavnespravy.sk.js"
      ]
    },
    {
      "matches": [
        "*://*.startpage.com/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/startpage.com.js"
      ]
    },
    {
      "matches": [
        "*://*.radia.sk/*"
      ],
      "js": [
        "js/jquery-3.4.1.min.js",
        "js/radia.sk.js"
      ]
    }
  ]
}