Many modern programs “integrate” (to varying degrees) with common SCM tools.
It would be nice if KiCad offered this feature too (e.g. files that have changed can be displayed differently in the project viewer, for example).
This is a great addition to the git plugin that I have developed in the future.
More discussion about this here - Github footprints problem
This mythical future tool would be abstracted beyond just using Git - other SCM tools could be supported also.
Each library (.pretty, .sweet) could support the same tool to show that there are library updates available, etc.