The Nostrum Protocol team has recently released a new NIP (Nostrum Improvement Proposal) that defines a new event type for classified listings. This new event type can include any product, service, or other thing for sale or offer with enough structured metadata to make them useful. The new event type includes two subtypes for saving drafts or inactive listings. The `kind:30402` event has a `.content` field that describes what is being offered and by whom, while the `kind:30403` event has a `.content` field that saves draft or inactive listings.

This new NIP will help improve the functionality of the Nostrum Protocol and provide more options for users who want to buy or sell products on the platform.

Link: https://github.com/nostr-protocol/nips/blob/master/99.md