From this tweet:
The things you find…. #Amiga source code to Menace. Has a label under it saying “Draconia source” #DMADesign pic.twitter.com/vCUYnTWkn7
Update: Brian Watson has identified his handwriting, and the disk is therefore the Atari ST source code for Menace! This makes sense, since “Draconia” was an early working title. Not as early as Coppercon1, which was named for an Amiga graphics chip register.