The release notes for z3 version 4.6 mention a new feature "issuing multiple (check-sat) calls until it returns unsat".
Is this an equivalent for ALLSAT?
Where can I find any further documentation or an example for this feature?
No, this was for addressing this issue: https://github.com/Z3Prover/z3/issues/1008
An ALLSAT command is not supported by z3; though it would be easy to code it using the "assert the negation of the previous model and re-check" loop. Most high-level interfaces provide this as a layer on top of what's possible using SMT-Lib2. If you do want support for this, it might be best to first convince the SMTLib folks (http://smtlib.cs.uiowa.edu/) so a standard way of doing so would be developed and can be implemented by multiple solvers.