Examine source code of Reddit Refine

{
  "manifest_version": 3,
  "name": "Reddit Refine - Filter, Analyze",
  "id": "https://addons.mozilla.org/en-CA/firefox/addon/reddit-refine/",
  "version": "1.4.0",
  "author": "ShriPunta",
  "description": "Removes posts matched by the configured filter from the reddit feed.",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.reddit.com/",
        "*://reddit.com/",
        "*://www.reddit.com/r/all*",
        "*://reddit.com/r/all*",
        "*://www.reddit.com/r/popular*",
        "*://reddit.com/r/popular*",
        "*://www.reddit.com/user/*",
        "*://reddit.com/user/*",
        "*://www.reddit.com/u/*",
        "*://reddit.com/u/*",
        "*://www.reddit.com/best*",
        "*://reddit.com/best*",
        "*://www.reddit.com/hot*",
        "*://reddit.com/hot*",
        "*://www.reddit.com/new*",
        "*://reddit.com/new*",
        "*://www.reddit.com/rising*",
        "*://reddit.com/rising*",
        "*://www.reddit.com/search*",
        "*://reddit.com/search*"
      ],
      "js": [
        "index.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "action": {
    "default_popup": "popup.html",
    "default_title": "Reddit Filter Settings",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png"
    }
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "reddit-filter@ShriPunta",
      "data_collection_permissions": {
        "required": [
          "locationInfo"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  }
}