The only place in Xeen this is used is drinking out of the well in Vertigo. The reason for this editing instruction is totally unknown, since the HED files are stored in the CC file, and not the SAV files, and therefore not remembered between loads and saves. Even in the context of the well, it makes no sense. Best guess suggests this was originally intended to serve a different purpose but was either never completed, or the original purpose of files changed and this instruction became useless. This opcode can safely be ignored.