TclStubs.tcl_ListObjAppendList

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
struct TclStubs
extern (C)
int function(Tcl_Interp* interp, Tcl_Obj* listPtr, Tcl_Obj* elemListPtr) nothrow tcl_ListObjAppendList;

Meta