Abstract
Reservatum rusticum was generally understood as a material obligation to perform (in natura, in reluto, work, acts, benefits and other services) attached to the farm (farmsteads). Given that the ABGB did not contain an explicit regulation of this contract (it was treated together with real burdens), it was indeed an expression of rural customary law.
However, the case law was aware of the distinction between an obligation and reservatum rusticum having real rights effects (the precondition was its entry in the land register). The content of this obligation was typically the duty of the new owner (or the incoming farmer) for the purpose of maintenance and provision of the original owner (outgoing farmer) to provide temporarily (typically for life) certain services, which consisted mostly in accommodation, transfer of a piece of land, benefits in kind from holding (eg milk, grain, eggs, meat), or other acts (provision of clothing, footwear, wood for heating, payment of expenses for a decent and adequate funeral etc.).
It was often the duty to endure something (eg taking water from a common well).