Bolt has a break-point feature. Select a connection, right-click and you will see an option to add a break-point. Bolt has a breakpoint feature. Select a connection, right-click and you will see an option to add a break-point. 

A break-point will turn the connection between the nodes red. 
When in play mode a  break-point error will appear in the log. The connected nodes are highlights with a yellow square. 

Clicking the error in the console will highlight the game object the script is attached too.

The one thing adding a break-point does not do is add a visual representation to the C#Preview. 

Expected 
A Brake point visual representation should be added to the C#Preview.  Alternatively, highlight the code that the connected nodes are generating.  

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