The PakBlacklist-<BuildConfiguration>.txt is used to disallow some files to be packaged in the pak file.
This can be very helpful to reduce pak file size for mobile platforms.
To avoid the user-defined blueprint class Debug.uasset located in Content/Blueprints folder to be packaged in shipping build, one has to do the following steps:
1. Create the PakBlacklist-Shipping.txt file in Build/Android directory.
2. Insert the content "../../../MyGameName/Blueprints/Debug.uasset
3. Package the game
Source: https://docs.unrealengine.com/latest/INT/Platforms/Android/ReducingAPKSize/#packageblacklist
Add built data to the gitignore.
Includes data about a map for UE4.14 that is generated when the user builds it (surprise! :D).
Often gigabytes in size.
Definitely don't want it in your repository.
John Vandenberg