How to edit the Default-Sprite Material/Shader?

I see the source code for the Sprites/Default shader in the built in shaders download from the Unity archive. What I don't know is where to put that to be the new default sprite shader.
I tried putting it in Assets/Resources folder but still whenever I create a new SpriteRenderer it defaults to material Sprites-Default using shader Sprites/Default that is the unmodified version of Sprites/Default shader. It says Sprites-Default material exists in Resources/unity_built_in_extra but I cannot find that folder.
Is it possible to change the default Sprites-Default shader so that every time I create a new SpriteRenderer it will start with that changed Shader? I'm on OSX if that affects folder locations

 

One reason which I have recently come across is the ability to set HDR colors. Currently, there is no easy way to make a sprite glow using an HDR/Emissive color...

 

Just make it a shader file with it's own shader name, and make materials that use this shader and apply the material to the SpriteRenderer component for sprites you want to have glow.

 

I have no experience making shaders either with code or with Shader Graph. Any tips you can offer would be greatly appreciated.