When using the Xcode 8+ and creating a new blank project, the following logs appear when running the application:
2016-06-13 16:33:34.406093 TestiOS10[8209:1
This is related to a known issue with logging found in the Xcode 8 Beta Release Notes (also asked an engineer at WWDC).
When debugging WatchOS applications in the Watch simulator, the OS may produce an excessive amount of unhelpful logging. (26652255)
There is currently no workaround available, you must wait for a new version of Xcode.
EDIT 7/5/16: This is supposedly fixed as of Xcode 8 Beta 2:
Resolved in Xcode 8 beta 2 – IDE
Debugging
- When debugging an app on the Simulator, logs are visible. (26457535)
Xcode 8 Beta 2 Release Notes