Unity generates an XAML C# Visual Studio solution. With XAML C# solution generated you are able to use managed assemblies, such as UnityEngine.dll, Assembly-CSharp.dll, etc. with XAML code on top.
Unity will create files like resources, vcproj, xaml files. If you build a project on top of the same directory, these files will not be overwritten:
It is safe for you to modify these files, and if you want to revert to previous state, just remove the file, and build your project on top of the folder.
Note: Unity doesn’t modify solution and project files if they already exist on the disk. Visual Studio takes the whole Data folder, instead of individual files, so if new file is added to Data folder, it’s automatically picked.
Generated Visual Studio projects have three configurations: Debug, Release and Master. Debug configuration has various safety checks and runs slower, Release configuration removes all those checks, but leaves profiler enabled. Master configuration should be used for final build that you submit to Store.
If you see Development Build text on the lower left corner, it means the game was not build for submission. This text will be shown, if you select Development Build when building form Unity, or if you’ve build Debug or Release configuration.