Question about CanvastTexture Specular & Shininess behaviour

Godot Version

Godot 4.5.1 stable win64

Question

For context i’m coming from a pbr metal/roughness 3d background,
I’m currently a little bit confused about how the canvas texture uses it’s textures and the documentation doesn’t seem to answer my questions regarding it’s specular & shininess behaviour.

I’m currently trying to figure out how the specular & shininess functions in godot in a 2d enviroment.

diffuse - rgb + alpha png to control color & opacity/transparency
normal - rgb / rg to control normals
specular - rgb + alpha ? for controlling specular intensity, color AND shininess factor ?

The specular can be controlled through a texture (either grayscale or color) , but can the shininess factor also be controlled by a texture ? From testing the alpha channel it does seem to have some type of affect but i’m quite puzzled by what the workflow/thought process for using it would be.

Does this override the shininess “slider” setting, or does the slider act as a multiplier ontop to control this?

Any insights would be greatly appreciated

It’s likely a multiplier.