OAuth 2.0 `.well-known/openid-configuration`?

I'm building a Flutter application using OAuth 2.0. Flutter's AppAuth package mention that any OAuth 2.0 system should be supported, however the process fails with the following:

`Error retrieving discovery document: JSON error parsing document at 'https://app.alpaca.markets/.well-known/openid-configuration': The data couldn’t be read because it isn’t in the correct format.`

When I try to access the URL, I realize Alpaca redirects to the main page and doesn't show something similar to other OAuth 2.0 providers (e.g. [IdentityServer4](https://demo.identityserver.io/.well-known/openid-configuration)).

Do you provide this well-known URL?