The stubs for them are already in SUO. When you have a script open, click the space to the left next to the line numbers. If the line can execute, the a breakpoint is added/removed. If you click the "Debug" tabs, you'll see the line where the breakpoints are located. Also, if you have breakpoints all over the place, then by clicking the breakpoints in the "Debug" tab, you will "zoom" your cursor location to the actual place in the code.
In the execution-enabled version, these do pause execution.