Again this info is from users/customers and not press releases so may be different for various versions:

Voyager

Export
Built in. Can export Marc with bib, holdings and authorities records, though marc is often mangled.
Database Access
Built in. Uses Oracle and also provides entity-relationship diagrams and some pre-build "views" to help in development. I believe the oracle license is also included in the base price. Access is read-only.
API's and Web Services
Built in. z39 access, however with SQL access you could likely build the API you need.