The same problem exists with verilog, i.e., the fact that you can have variations of verilog like the behavioral, the netlist, netlist with or without power supplies, testbenches, etc. I have seen "_tb.v" used for testbenches, also ".tv"; qflow uses ".rtl.v" and ".rtlnopwr.v" for gate-level netlists with and without power supplies (the names are misleading and I would have changed them except that they've infected all the scripts and it would take a lot of work to change them).