curl -Lv "http://unknown:invalid@httpbin.org/redirect-to?url=http://user:pass@httpbin.org/basic-auth/user/pass"

{
  "authenticated": true, 
  "user": "user"
}

*   Trying 54.210.149.139:80...
* Connected to httpbin.org (54.210.149.139) port 80 (#0)
* Server auth using Basic with user 'unknown'
> GET /redirect-to?url=http://user:pass@httpbin.org/basic-auth/user/pass HTTP/1.1
> Host: httpbin.org
> Authorization: Basic dW5rbm93bjppbnZhbGlk
> User-Agent: curl/7.88.1
> Accept: */*
> 
< HTTP/1.1 302 FOUND
< Date: Sat, 08 Jul 2023 05:51:30 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 0
< Connection: keep-alive
< Server: gunicorn/19.9.0
< Location: http://user:pass@httpbin.org/basic-auth/user/pass"
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Credentials: true
< 
* Connection #0 to host httpbin.org left intact
* Issue another request to this URL: 'http://user:pass@httpbin.org/basic-auth/user/pass"'
* Found bundle for host: 0x6000032ec060 [serially]
* Can not multiplex, even if we wanted to
* Re-using existing connection #0 with host httpbin.org
* Server auth using Basic with user 'user'
> GET /basic-auth/user/pass" HTTP/1.1
> Host: httpbin.org
> Authorization: Basic dXNlcjppbnZhbGlk
> User-Agent: curl/7.88.1
> Accept: */*
> 

< HTTP/1.1 401 UNAUTHORIZED
< Date: Sat, 08 Jul 2023 05:51:36 GMT
< Content-Length: 0
< Connection: keep-alive
< Server: gunicorn/19.9.0
* Authentication problem. Ignoring this.
< WWW-Authenticate: Basic realm="Fake Realm"
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Credentials: true
< 
* Connection #0 to host httpbin.org left intact