As of 10.02, Rosegarden uses new audio file naming conventions in order to help you keep track of which files go with which project.
When you drop an audio file onto the segment canvas, or record an audio segment, Rosegarden will create audio files in the audio path associated with the active composition. Their format is as follows:
rg-[composition filename]-[instrument alias]-YYYY-MM-DD_HH.MM.SS-n.wav
The composition filename is last name under which the active composition was saved. The instrument alias is the alias set for the audio instrument that was used to record the file, or the audio instrument in use by the track where the file was dropped. This will be “not_specified” is no instrument alias is set.