In VS2012 it’s as easy as going to C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class
and editing the Class.cs file.
No need to unzip or rebuild cache. A very positive change if you ask me.
VS2015: C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class
VS2017(RC): C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class
VS2017(Professional): C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class
VS2019 (Enterprise): C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class\Class.cs
VS2019 (Professional): C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class\Class.cs
Starting with Visual Studio 2022 VS is a 64 bit application, meaning the item templates are in C:\Program Files\...
instead of C:\Program Files (x86)
VS2022 (Community): C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class\Class.cs
VS2022 (Professional): C:\Program Files\Microsoft Visual Studio\2022\Professional\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class\Class.cs
VS2022 (Enterprise): C:\Program Files\Microsoft Visual Studio\2022\Enterprise\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class\Class.cs
Outdated
VS2019 (Preview): C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\ItemTemplates\CSharp\Code\1033\Class\Class.cs