Just saw this newly listed in YAJ:
https://page.auctions.yahoo.co.jp/jp/auction/j473219458
DSP Injection for X680x0
Only info that I found:
AWESOME-X
DSP high-speed computing processor board for X680x0 released from Gravis. MAX128,000bps RS-232C2 line, DigitalAudioInterFace, infrared terminal etc. equipped.
https://ht-deko.com/x68k.html
Gravis? ??? Is this a sound card with some kind of wavetable (DSP)?
Anyone know more details?