Finding operator Neural Network source code

Dear Rapidminer users.
I've been looking for the source code of the operator 'Neural Network' in order to find some details: such as activation function, cost function, optimizer etc it has used.
I've long looked through the Github Rapidminer page and searched the community but I just couldn't find it...

I would like to know if there is a source code of Neural Network available and if it is where I can find it
or if there is detailed info of Neural Network: used functions etc

Help would be great. Thanks!!!