How to find list of supporting simulink model extension in MATLAB.

After 2012a, ".slx" was introduced as Simulink model extension. i want a command which on executions gives result which all model format are supported in current version of MATLAB. I don't want to parse MATLAB version and get this information indirectly, i want if there is any function which gives list of model extension supported in any MATLAB version.

For 2012a "ModelFormat" give the partial result but it is not know to lower version of MATLAB.

I hope my question is clear. Thanks in advance.