You can create Custom AOVs for your project and send colors, float values, or integer values from a material to an AOV.
You can find more information about Custom AOVs here.
The concept of these nodes is the same, they offer inputs for colors, integer values, or float values and make them available to Custom AOVs.
By placing the Store Scalar To AOV node inbetwee the Material node and the Output node, we can add float values to the rendered material, that can be shown in a Custom AOV.
Use the AOV Input value to set the value that should be shown in the Custom AOV.
Use The AOV Name to choose an available Custom AOV to display your value. If there is no Custom AOV setup already, you can also choose Add new Custom AOV and enter a name for it here.