Examine source code of Libre Fixes JS

{
  "manifest_version": 2,
  "name": "Libre Fixes",
  "version": "1.3",
  "description": "A collection of work-around scripts for a few different websites that are impossible to use without non-free JavaScript. Goes with Libre JS",
  "icons": {
    "16": "icons/L4Libre.png",
    "48": "icons/L4Libre48.png",
    "128": "icons/L4Libre128.png"
  },
  "browser_action": {
    "default_icon": "icons/L4Libre128.png",
    "default_popup": "html/Test.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.wayport.net/*",
        "https://www.sumofus.org/*",
        "https://www.sumofus.org/campaigns/*",
        "*://*.actions.sumofus.org/a/*",
        "*://*.actions.sumofus.org/api/pages/*/actions",
        "*://*.actions.sumofus.org/*",
        "https://*.pay.gov/*",
        "https://dmca.copyright.gov/*",
        "*://rsf.org/*",
        "*://rsf.secure.force.com/*",
        "*://docs.google.com/*",
        "*://login-mcd-cluster.prd.snantx.attwifi.com/guest/*",
        "https://pgw.ceca.es/cgi-bin/tpv",
        "https://pgw.ceca.es/tpvweb/tpv/compra.action",
        "*://*.goteo.org/*",
        "*://*.sermepa.es/*",
        "*://old.reddit.com/*",
        "*://mail.google.com/*"
      ],
      "js": [
        "workaround/mcdonalds_wifi.js",
        "workaround/sumofus_main.js",
        "workaround/paygov_main.js",
        "workaround/rsf_main.js",
        "workaround/googledocs_main.js",
        "workaround/goteo_main.js",
        "workaround/Gmail.js"
      ]
    }
  ],
  "permissions": [
    "*://reg.usps.com/*",
    "*://production.shippingapis.com/*",
    "webRequestBlocking",
    "*://*.sumofus.org/*",
    "*://*.actions.sumofus.org/*",
    "webRequest",
    "*://*.pay.gov/*",
    "*://reddit.com/*",
    "*://www.reddit.com/*",
    "*://np.reddit.com/*",
    "*://amp.reddit.com/*",
    "*://i.reddit.com/*",
    "*://i.redd.it/*",
    "*://docs.google.com/*",
    "*://preview.redd.it/*",
    "*://mail.google.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{cd1c65ce-fb42-4e34-acb7-f001d4b6002d}"
    }
  }
}