iOS Debugging and Optimization - Learning Unreal Engine iOS Game Development - page 177

The Output Log screen not only prints messages from your blueprints' logic, but also
prints messages from the internal engine core. It is also a good place to follow the pro-
gress of building and packaging a playable version of the game. The Output Log screen
is a log for anything related to your Unreal Engine project—not only code and engine-re-
lated stuff, but anything else too. It is always a good place to check for the cause of
crashes or building and packaging failures.
The Output Log window has its own tagging system, and any printed line will have a tag
for itself. For example, a printed message from a Print String node in your blueprint will
usually start with LogBlueprintUserMessages: .