As known as Common Ownership Self-assessed Tax (COST) where individual property owners decide the value of the property/land they own based on their own self-assessment and then pay the property tax or Harberger Tax on the value they declare on the property.
However, here anyone can then propose to buy the property for the declared value amount. Here the rules are not clear as whether the property owner has to sell the property on a valid proposal and what will be the terms of transfer (time period, depreciation, insurance, defacement/vandalism of the property) or the owner refuses to sell, then perhaps there’s a re-evaluation of the properties value by the proposer.