The Dreamweaver product sometimes removes old features that are no longer used enough to justify their maintenance cost. If the feature can be still be provided as an Extension, the the DW Team tries to provide that code on an “as is” (i.e. unsupported) basis.
Start by looking in this folder to find some old Server Models:
Also, check the Dreamweaver Exchange:
Then search for the Feature name. For example, you can find the old table-based Starter Pages here:
Are there any other old features that you’d like to be able to install as an extension?