Here is a patch to provide default gucs for EXPLAIN options.
I have two goals with this patch. The first is that I personally *always* want BUFFERS turned on, so this would allow me to do it without typing it every time.
The second is it would make it easier to change the actual default for settings if we choose to do so because users would be able to switch it back if they prefer.
The patch is based off of a995b371ae.
It's lot of new GUC variables. Isn't better only one that allows list of values?