Breakpoints are a way of pausing your program on a particular block in your code so that you can see what CodeBug is doing after the block has been ran. You usually set breakpoints in places where you think the error could be, or places where you can’t observe an intermediate step of the program.

You can set breakpoints by right clicking the block and selecting "Set Breakpoint" or clicking the breakpoint button next to the undo/redo buttons.