Yes! All module files are signed using Automox's PKI.
Currently, WDK is only designed to target Windows. Stay tuned, though, as a Bash implementation is underway for release in the very near future!
At this time, direct code contribution to WDK is not possible. This is a concept we will continue to evaluate as the WDK function collection grows and adoption increases.
In the meantime, any potential feedback or contributions are welcome and greatly appreciated over on the Automox Community in the Worklets section.