[oe] right directory for a recipe

[Andrea Galbusera]

Hi,

I'm planning to port a recipe from oe-classic to meta-openembedded and
submit patches to the list. The particular recipe is libmodbus, but my
question is more general.
I looked around for documentation suggesting how meta-oe/ dir is laid
out, but found nothing in particular. Any pointer here?
What would be the right directory to put libmodbus in? I understand
recipes-* names are somewhat self explanatory, but I'm still confused
if "recipes-extended", "recipes-support" or anything else is the best
choice.

TIA
Andrea