To check user permissions in Lightning web components, a developer should import two scoped modules: @salesforce/permission and @salesforce/customPermission. The @salesforce/permission module allows the developer to check if the user has access to a standard permission, such as View Setup or Modify All Data. The @salesforce/customPermission module allows the developer to check if the user has access to a custom permission, such as Enable Debug Mode or Manage Orders. The other modules do not exist or are not related to user permissions. Salesforce Reference: Lightning Web Components Developer Guide: Check User Permissions, Lightning Web Components Developer Guide: Import Salesforce Modules