Examine source code of Social Silence

{
  "name": "Social Silence",
  "description": "Hide user reactions on Facebook like emoji reactions, discussions, shares...",
  "version": "1.0.4",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "social-silence@rgertler.de"
    }
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "./images/icons/favicon-16x16.png",
      "32": "./images/icons/favicon-32x32.png",
      "48": "./images/icons/favicon-48x48.png",
      "128": "./images/icons/favicon-128x128.png"
    }
  },
  "icons": {
    "16": "./images/icons/favicon-16x16.png",
    "32": "./images/icons/favicon-32x32.png",
    "48": "./images/icons/favicon-48x48.png",
    "128": "./images/icons/favicon-128x128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "scripting",
    "tabs",
    "https://*.facebook.com/*"
  ]
}