Sound file entry -What is this ?

[PROP.1.01]filename=flags=4viewpoint=1rparams=0.000000,0.794000,0.500000,1.149000vparams=0.012000,0.000000,0.178000,0.800000,0.248000,1.350000,0.618000,2.750000,0.725000,0.000000,0.815000,0.000000,1.000000,0.000000,1.000000,0.000000link=PROP.1.02What does it mean when the entry says filename= ( with no mention of a file) Thanks Barry