SimpleProgramDebugger is a tiny tool which can display the main debugging events in a process: Load DLL, Unload DLL, Create Thread, Create Process, Exit Thread, Exit Process, Exception and Debug String.
As usual with a debugger, you're able to attach to a running process, or start a new process in debugging mode. You can't then control anything, so it's just a matter of watching as debugging events listed as they happen: event time, type, thread ID, memory address, file name and "More Information". Detach from the process when you're done, and the report can be saved as a TXT, CSV, XML or HTML file.
If you think this sounds highly technical, then you're right. Debuggers are used by developers for low-level analysis and troubleshooting, and most of the details here will be utterly meaningless to anyone else (even Windows and PC experts).
Still, SimpleProgramDebugger can occasionally provide interesting information about a program. We used it to launch our Firefox installation, for example, and found previously unseen "debug string" messages including "Failed to load native module at path...", "Could not read chrome manifest 'file@///" and "...could not create service for entry...". Are these messages normal? We've no idea, but if Firefox were misbehaving then this is just the type of information which might point us in the right direction.