Examine source code of OpenModHeader

{
  "manifest_version": 3,
  "name": "OpenModHeader",
  "version": "1.2.2",
  "description": "Add, rewrite, and remove HTTP request and response headers. Organise rules into profiles and scope them with URL filters.",
  "browser_specific_settings": {
    "gecko": {
      "id": "openmodheader@openmodheader.local",
      "strict_min_version": "115.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "storage",
    "alarms"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "type": "module"
  },
  "action": {
    "default_title": "OpenModHeader",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "commands": {
    "toggle-pause": {
      "suggested_key": {
        "default": "Alt+Shift+H"
      },
      "description": "Turn OpenModHeader on or off"
    }
  }
}