Examine source code of PistonHeads User Blocker

{
  "manifest_version": 3,
  "name": "PistonHeads User Blocker",
  "version": "1.2.2",
  "description": "Hide posts from selected users on the pistonheads.com forum",
  "permissions": [
    "storage"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.pistonheads.com/gassing/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "phblock@phables.co.uk"
    }
  }
}