Research the extra byte introduced in RSW 2.6 (build no. 162) and document it

[rdw-software]

Analysis results (value = count):

unknownRenewalPropFlag = {
  [0] = 743205,
  [1] = 208,
},

May be related to a potential change in data layout for the props? Possibly blocked by #78 , #79 in this case.