I'm with Robert on this one. I'm a grudging +1 to buffers defaulting on, and a strong -1 to all the other proposals. Guillaume, the patch looks pretty good. I would like to see some of the example output have more than just "shared hit" and "read" though: let's throw some "dirtied" and "written" in there as well.
It defaults to <literal>TRUE</literal> when <literal>ANALYZE</literal> is also enabled. Otherwise, it defaults to <literal>FALSE</literal>.
Is that second sentence really needed? Because "BUFFERS ON" will never be needed anymore (save as a no-op to allow the same explain queries to run cross-version), and BUFFERS OFF outside of analyze is meaningless.
Cheers,
Greg