Thanks for your reply. In this case, the issue is not a special edition on India.
In particular, the article billed as "EXTRA" is not accompanied by any other articles
on related themes.
So I don't think your conjecture, reasonable as it is, answers my question.
i suppose it's a possibility that the length of each issue, or the number of articles,
is somewhat standardised, and that LRB are saying that they're increasing this number
(or length) and attributing the increase to that "EXTRA" article, which is kind of an insult
to the other contributors.
Or it could be that the "EXTRA" article is given premier billing, as being particularly
outstanding/interesting/newsworthy etc. (which is very similar [maybe even the same] as what
you suggested).
Paul Epstein