One of my apps keeps spawning the following in the Console
DEPRECATED USE in libdispatch client: dispatch source activated with no event handler set; set a breakpoint on _dispatch_bug_deprecated to debug
Any ideas?
BTW only seems to be on macOS 10.14
Based on what you put there, Apple deprecated parts of libdispatch in 10.14.
Do you get these same console messages with an empty app?
Will test this later. But my guess it is not. 
Isn’t libdispatch related to preventing the system to Sleep ?
According to a google search libdispatch is the binary name of Grand Central Dispatch.