[vore]

Leading comma is better at resolving textual 3-way merges, e.g.:

   [ a         [ a       [ a
   , b         , b    /  , b
   , c   -->   , c   /   , c
   , d         , d  /    , dd
   ]           , e       ]
               ]

Your usual 3 way merge algorithm will correctly deduce:

   [ a
   , b
   , c
   , dd
   , e
   ]

Contrast this with trailing comma:

   [ a,         [ a,       [ a,
     b,           b,    /    b,
     c,   -->     c,   /     c,
     d            d,  /      dd
   ]              e        ]
                ]

You now have a merge conflict between "d," and "dd".

However, if you were to require a trailing comma after the final element you wouldn't have this problem.

[Izkata]

> Contrast this with trailing comma:

Example doesn't have a trailing comma. If it did, it would act the same as the leading comma.

But also the leading comma just moves the problem to the beginning of the list instead of the end. Trailing comma with the opening [ on its own line wouldn't have that problem anywhere.