Unused Data

This message is printed by the internal xEdit error check.

"Unused data means that while parsing, xEdit has reached the end of the value definition for that subrecord, but there are more bytes in the subrecord." - ElminsterAU

For example, this can happen if a plugin made for a newer game version (Skyrim Special Edition) is used with a game mode of an older game version (Skyrim Legendary Edition).