Do wildcards still work?

This post says wildcards work on subdomains: 

https://community.constantcontact.com/t5/API-Developer-Support/New-Authorization-Service-and-Using-Wildcards/m-p/382533#M12868

This one mentions it's deprecated in certain places: 

https://community.constantcontact.com/t5/API-Developer-Support/Wildcard-deprecation/m-p/397017?lightbox-message-images-397017=30946i80A0F19731D4962D#M13850

Is there documentation/examples on what is actually supported?

I just tested the following, which was accepted by the UI but didn't work: 

https://*.dev.mydomain.com:1234/TestingPath/

I had to change it to: 

https://myname.dev.mydomain.com:1234/TestingPath/ 

And that worked. 

Is it not working because the wildcard is on a 2nd level subdomain or because wildcards are now simply deprecated?