How Could I Use Source Code in Developer Directory?

Hello,

I recently referenced the FileUtilities module in my game. The module’s source code is located in Engine/Source/Developer/FileUtilities/Public/FileUtilities/.

When packaging my game, UBT reports an error:

Non-editor build cannot depend on non-redistributable modules...

I found that there is a function IsRedistributable in UEBuildTarget.cs which marks every thing in Source/Developer as non-redistributable.

My question is, why I cannot use source code in the developer directory and if I just copy and paste the code into my game module, of course UBT would no longer prevent me from using them, but is there any legal risk?

Thank you