accessory thing of transactional subject and results of its absence

accessory thing is a thing that stands in a dependency relationship with the principal thing. an accessory thing ordinarily serves the economic or other purposes of the principal thing and shares its legal fate in case of transfer or encumbrance. there are some questions? different opinions about the meaning of it and the is it a contractual subject or not? and may it be determined by implicit statements or not? the task of ascertaining the intention of the parties must be approached objectively: the question is not what one or other of the parties meant or understood by the words used, but “the meaning which the document would convey to a reasonable person having all the background knowledge which would reasonably have been available to the parties in the situation in which they were at the time of the contract.