1. Go to "Tools" -> "Options..." -> "Kits" -> "Kits".
2. Select a Kit.
   I tried one using MSVC2015 64 bit.
3. In the "Name" edit, click on the "A->B" icon.
4. Select "Kit" -> "Compiler:Name" from the list of variables.
   No value for the variable is shown in the Variables window:
   

When using the variable in the kit's name, it will expand to the correct value. The Variables window should show this value, too.