Can anyone else confirm this? We have many old web site projects that we're moving to web app projects and we make heavy use of the "convert to web app" context menu option for aspx files. I installed VS2013 this morning and the option does not show up. Was it taken out, or is something not configured correctly?
You can check this pretty easily by making a new web application, removing the designer file for default.aspx and then right-clicking the aspx file.