Spec: where is blocksize defined / stored

[barthanssens]

The page http://www.rdfhdt.org/hdt-binary-format/ mentions BlockSize, but does not say what this value is or where it is stored

This DictionarySection implementation stores strings in blocks of “BlockSize” string

Is it set using the hdt:hdt:dictionaryBlockSize property (see http://www.rdfhdt.org/hdt-internals/) that is part of the Header n-triples data ?

If this is indeed the case, this probably means that an implementation, in order to read the HDT files, always has to parse this n-triples data just for obtaining this value.
(or is the blocksize value perhaps also stored in another Control Information comma-delimited property ?)