Twitch User Converter
Twitcher comes with an inspector for TwitchUser resource when you have the editor authorized. It helps you to convert the UserNames to User IDs with the help of the TwitchAPI. For convenience purpose, it converts the Username directly to a TwitchUser Resource and you can use it where ever you want.
Example:
@export var user: TwitchUser[Export] public TwitchUser User { get; set; }C# note
The editor tooling on this page (the inspector, the authorize/convert buttons, the screenshots below) works identically no matter which language your scripts are in; it's driven by the exported TwitchUser property itself, not by GDScript or C#.
It looks like this when authorized: 
And when unauthorized: 
When you see the unauthorized editor in a Twitcher Node and you don't want to authorize the editor. You normally have to enter the user id.
See also Editor Authorization for how to authorize the editor.