KitDLL is a single-file Tcl (and optionally Tk) library. Normally, libtcl and libtk still require the external Tcl-initialization scripts and other external resources (and in fact "tclsh" is a very tiny program which just invokes libtcl). Just as it is sometimes desirable to have a single-file executable distribution of Tcl (Tclkit/Basekit) it is sometimes to have this distribution in a single-file library.
KitDLL is to shared objects, libraries, or DLLs what Kitcreator is to executables.
The KitDLL project is slightly different from the KitSH (Tclkit/Basekit) project in the way the internal Virtual Filesystem (VFS) is stored. In the KitSH project the VFS is added after compile-time and the executable MUST be able to find itself to open this VFS. In the KitDLL project the VFS is added at compile-time so that the library does not have to be found on the filesystem for initialization since this cannot be guaranteed to be possible on the platforms Tcl supports.