Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
You asked for multi party protection, and rush told you that idea was ruled out. Here is the background. It sounds reasonable: several named nodes can read this data, and nobody else. But a decision was made that this level does not exist. Protection has exactly four levels: none, transport, at rest, and end to end for one recipient. The word multi party is still known to the engine, but only so that, when someone reaches for it, rush can refuse by name and point to the ruling, instead of saying that the word is unknown, which would suggest a typo. This is the difference between a retired idea and a mistake. The message names the manifest, the line, and the word, and the second slot lists the words that are actually applied. So what can you do? If only one node should read a value, use end to end with that recipient. If you only need the data safe on disk, use at rest. Choose the closest honest level, and run again.
Text from the Rush engine's error catalogue.