Examine source code of FurAffiniTweaks

{
  "manifest_version": 3,
  "name": "FurAffiniTweaks",
  "browser_specific_settings": {
    "gecko": {
      "id": "furaffinitweaks@abtmtr.link"
    }
  },
  "version": "0.5",
  "description": "Site tweaks for FurAffinity, making the site more tolerable overall.",
  "icons": {
    "48": "icons/fua-48.png",
    "96": "icons/fua-96.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "web-accessible/furaffinity.net/*"
      ],
      "matches": [
        "*://*.furaffinity.net/*"
      ]
    }
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.furaffinity.net/*"
      ],
      "js": [
        "scripts/furaffinity.net/loader.js"
      ],
      "css": [
        "styles/furaffinity.net/style.css"
      ],
      "run_at": "document_start"
    }
  ]
}