Location where Keyboard Mapping Scheme is drawn from in Tools->Options is: C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE
Location where Current.vsk and imported VSK files are put: C:\Users[user]\AppData\Roaming\Microsoft\VisualStudio\14.0
Default location for exporting settings (.vssettings XML file) c:\users[user]\documents\visual studio 2015\settings
OOB Keyboard Mapping Files: VS/src/VSCommonContent/profiles/keyboardSchemes eg. Visual CSharp 2005.vssettings