What is signin-auth?

I am developing an ASP .Net Core MVC web app which calls a web API using the "Authorization Code Grant Flow". I am using Auth0 for the authentication server. I see in a lot of their examples, the redirect_uri is "http://localhost:60856/signin-auth" - what is signin-auth? Is it a controller I need to implement in my web app?

for example:

<a href="https://codexcreations.eu.auth0.com/authorize?scope=appointments%20contacts&audience=appointments:api&response_type=code&client_id=goOFNvxZ2tlti2Xi4pBitP50BtGunibl&redirect_uri=http://localhost:60856/signin-auth0">
  Sign In</a>

Also, if anyone has any ASP .Net Core MVC samples using the "Authorization Code Grant Flow" I would greatly appreciate it. Thanks