Examine source code of Header Override

{
  "manifest_version": 3,
  "name": "Header Override",
  "version": "0.2.6",
  "description": "Modifica request header HTTP, stile ModHeader (Firefox MV3)",
  "author": "Massimiliano Pili",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "lib/matcher.js",
      "lib/applier.js",
      "lib/storage.js",
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup/popup.html",
    "default_title": "Header Override",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "commands": {
    "toggle-global": {
      "suggested_key": {
        "default": "Ctrl+Shift+H"
      },
      "description": "Toggle all header overrides"
    },
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+U"
      },
      "description": "Open Header Override popup"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b2f8e4d6-9a3c-4f7e-8d1b-5c6a9e3f7b2d}",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}