ADFS : Pre-populating the user on the login screen

This question often comes up and I came across a site that does this.

Note this is with ADFS 4.0 (Server 2016).

The URL is:

GET https://my-adfs.cloudapp.net/adfs/ls/?login_hint=myuser%40dev.local
&wctx=Yue...BfN-A7v
&wtrealm=some_realm
&wa=wsignin1.0
...
etc

The ADFS login screen then looks like:

Enjoy!