Examine source code of HideSteamHeader

{
  "manifest_version": 3,
  "name": "HideSteamHeader",
  "version": "1.0",
  "description": "__MSG_extension_description__",
  "default_locale": "en",
  "icons": {
    "16": "icons/off16.png",
    "32": "icons/off32.png",
    "48": "icons/off48.png",
    "128": "icons/off128.png"
  },
  "permissions": [
    "declarativeNetRequest",
    "tabs"
  ],
  "host_permissions": [
    "*://*.steamcommunity.com/*",
    "*://*.steampowered.com/*"
  ],
  "action": {
    "default_title": "HideSteamHeader",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/off16.png",
      "32": "icons/off32.png",
      "48": "icons/off48.png",
      "128": "icons/off128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "matxia@hidesteamheader",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}