the graph file.
These positional references are stored as unsigned 32-bit integers
-corresponding to the array position withing the list of commit OIDs. Due
+corresponding to the array position within the list of commit OIDs. Due
to some special constants we use to track parents, we can store at most
(1 << 30) + (1 << 29) + (1 << 28) - 1 (around 1.8 billion) commits.