Setting fallback to Sprites-Default on custom shader for sprites

Hello,

I have a custom shader that I’m using to outline sprites. I would like to set a fallback to revert to the “Sprites-Default,” but I’m not sure what the line would be.

I’ve tried:

fallback “Sprites-Default”
fallback “Default”

I understand that Sprites-Default is technically a material, but I don’t know what the shader for it is. This is the error I get from using fallback “Default”

Shader ‘Sprites/Outline’: fallback shader ‘Default’ not found

I know this is an old question but I’l leave an answer for other people, you can use: Fallback “Sprites/Default”.