What it is, how to use.
In your shaders created with WGSL (Composition User Defined Shader) you can now pass inputs into the shaders. To do this, create a Dictionary with the values you need. Then, use those parameters in your shader code. This approach provides a mechanism for creating configurable and animatable effects.
Example
The liquify tool is an example of this strategy. This tool allows you to configure frequency and amplitude — controlling the strength of the effect. Take a look at how this tool works to get started making your own shaders with inputs.