Describe the project you are working on

I Work on a 2D game using differrent animation for each character with a variant system.
i use a Animation Player for moving the offset of my sprites, the library is an "action" and the animation in it are "variant of this action".

Describe the problem or limitation you are having in your project

It is hard to set up character inherited scene libraries from editor.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Having the libraries dictionary tiped make it more easy to set up and makes errors less likely to occur.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Set a StringName, Set a Library, and push a button to add it to the libraries

If this enhancement will not be used often, can it be worked around with a few lines of script?

This can be worked arround with plugin or tool script but this can mean more code for do the same simple thing

Is there a reason why this should be core and not an add-on in the asset library?

AnimationMixer is a core Node and this fonctionnality simplified is use