SWA
From Just Solve the File Format Problem
Macromedia licensed the MP3 technology in 1995 to use in their Shockwave product. .SWA or Shockwave Audio was originally added as a free plugin to SoundEdit 16 to export AIFF files to .SWA.[1][2]
File Format
.SWA files have the same structure as MP3 files but with padding at the beginning of the file. Samples show the hex values 00 00 01 40 00 00 00 03 00 00 AC 44
for the first 12 bytes. No ID3 tags obviously.