CS6 comes with ExtendScript ToolKit 3.8. It allows you write scripts to extend features / automate tasks in Adobe products like Photoshop, Bridge and Dreamweaver.
"The ExtendScript Toolkit provides an interactive development and testing environment for ExtendScript in
Unicode capabilities and multiple undo/redo support. The Toolkit is the default editor for ExtendScript
files, which use the extension .jsx."
Alt-Web Design & Publishing
Web | Graphics | Print | Media Specialists
Dreamweaver Developer Toolbox (ADDT) was discontinued a few years ago. Dreamweaver CS4 is the latest version with which ADDT is compatible.
If there are specific features/workflows from ADDT that you would like to see added to Dreamweaver, please let our development team know directly: http://adobe.ly/DWwish
I would also recommend asking in this forum about what you are trying to accomplish.
If Dreamweaver can't do what you want, one of the experts here can advise you on how to accomplish it (for example, there may be an extension available).