.prx files

[Fred Grant]

I'm accumulating the above files in my home directory.  Does anyone know 
what they are?

.prx0Wbh8A                         .prx2MMzOz                          
.prx6LcHVo                                 
.prxdQChbw                              .prxEn6jXa                      
  .prxIHKZrc                          
.prxKheaLr                              
.prxqnp9dY                              .prxU6DNY0

The above are some examples.  They seem to be small binary files.

Thanks