User Portlet User Portlet

Discussions
You can describe a Python function in words by putting triple quotes at the top, so that appears in Help. Is there a way to do that in Mathematica?
When I use PlotLegends -> "Expressions" in a multiple plot, it works okay. But the colorbars to the left that differentiate the functions are so thin I can't always make out the different colors. Is there a way to make them thicker, or choose more...
The similarity of Wolfram graphs made me think of neural nets. Is there anything in the Wolfram physics system similar to back propagation? In nature, all complex systems have some form of feedback or back propagation.