Oric-dsk-manager exported file
From Just Solve the File Format Problem
The oric-dsk-manager software, when extracting individual files from a DSK file, adds what it calls a "custom header" to each file.
It has not been confirmed that this container format is actually specific to oric-dsk-manager.
Format details
An exported file starts with a 12-byte header. The original file data immediately follows.
The header consists of the ASCII signature "SEDORIC
", then a 2-byte load address, then a 2-byte exec address, then 1 byte for flags.