The metadata vault, "! LastPass Imported Shared Folders Metadata", stores data that associates the LastPass folder IDs with the newly created shared vault UUIDs. This is how 1Password can update permissions for previously imported shared vaults.

This is a required part of the import tool. Without it, permissions cannot be imported for previously imported folders, and there is increased risk of duplication of Shared Folders with future import runs.

The vault will remain in place until all import activity is done. Removing the vault, or altering its permissions, could prevent some aspects of the import tool from functioning as expected.