Here's a clear summary based on your source and Windows community/engineer explanations:
Why You See a Blank or Unnamed Program Blocking Windows Shutdown
When you shut down your PC, Windows sends a message to all running programs and background services asking them to close safely.
Sometimes...
background processes
dummy windows
process management
raymond chen
shutdown resolver
shutdownblockreasoncreate
software development
system security
system stability
task manager
unsaved work warning
windows apps
windows background services
windows central
windows comments
windows explanation
windows shutdown
windows system issues
windows system tips
windows troubleshooting
For decades, Windows users have been bewildered by the appearance of an anonymous window that blocks system shutdowns, often marked only with a vague message or a blank space where a program name should appear. This cryptic occurrence has left even seasoned PC enthusiasts perplexed, especially...
background applications
blocked shutdown
bsdr
helper windows
microsoft windows
program windows
shutdown diagnostics
shutdownblockreasoncreate
system processes
system security
system shutdown
user troubleshooting
windows
windows api
windows background processes
windows development
windows forums
windows internals
windows tips
windows troubleshooting