strapi/examples/getstarted/extensions/users-permissions/config/routes.json

{
  "routes": [
    {
      "method": "GET",
      "path": "/custom-route",
      "handler": "UsersPermissions.customRoute",
      "config": {
        "policies": ["plugins.users-permissions.customPolicy"]
      }
    },
    {
      "method": "GET",
      "path": "/",
      "handler": "UsersPermissions.index",
      "config": {
        "policies": ["plugins.users-permissions.customPolicy"]
      }
    }
  ]
}