http://ttevhjjsjxz6uqqcjkbig5cycd7n7xv7cmd6f5fcvrqaaa7f3bj36wad.onion/technology/security/pow/index.html
How do I know as an end-user that an Onion Service is under stress? ¶ As of August 2023, sites under stress will either be slow or even time out, but
without a user interface indicating that the PoW protection is active. Applications like Tor Browser could display, in the future, whether PoW is
enabled in a service and it's suggested effort level for the client puzzle,
which could be used to guess if a service is under stress.