You can simulate a synthesized netlist to verify that the synthesized design meets the functional requirements and behaves as expected. Although it is not typical, you can perform a timing simulation with estimated timing numbers at this simulation point.
The functional simulation netlist is a hierarchical, folded netlist expanded to the primitive module and entity level; the lowest level of the hierarchy consists of primitives and macro primitives.
These primitives are contained in the UNISIMS_VER library for Verilog, and the UNISIM library for VHDL.