This is really nice, by default it seems the sheet is shared with one additional nPub. Is the the nPub from the tool itself?
Discussion
It creates a new public key for each spreadsheet so that you can share that key with other editors later. :)
The private key is encrypted to each p-tag in the event, so everyone that you share gains full access to the replaceable event without having to control any off-line storage for the key.