Hello Ralph,
This is not simple. This is a generic method that does not have anything specific to do with workflow, it can be called from anywhere.
To further complicate matters, the inbox launches it asynchronously, so there is no call stack that you can investigate. There are a variety of other scenarios: What if the link is clicked from a web inbox or POWL, where it may work differently.
The actual launch happens via transaction SWO_ASYNC, you can do some debugging to see if there's any useful data you can extract.
Regards,
Mike