Built on powerful and elegant long-standing principles, the core Mathematica language has been gradually enhanced under tight control over its twenty-year history. Version 6.0 added convenient new list manipulation functions and enhanced pattern matching and options handling, as well as a major new integrated debugging and code analysis system.
ReplacePart (modified) — now supports general sparse rule specification
Debugger — full interactive debugging and code analysis environment
New ▶ Package (.m) — special notebook editor for package files, with function indices
TreeForm (modified) — graphical display of the tree structure of an expression