What is this hole in my porch called?
Provided it is open at the bottom and top, it's a combination 'access to the crawl space' and 'porch drainage'.
I have done a number of searches based on 'Craftsman porch design', and I cannot find a special name for it.
It appears to be a classic field stone arch. Most of these homes have a latticed skirting covering the access to the crawlspace. They provide ventilation to the underparts of the porch, which unless airy, can become a dark and dank snake and rodent haven. When dry, our canine companions find it a cool place to take a snooze, especially during the dog days of summer*.
*I seem to recall a Michael J Fox movie filmed in Georgia, and a sweat-gland-less family that sleep beneath their porch during the hot nights.
Update:
Phil Sweet has suggested 'scupper', and I thought that was only nautical, however,
an outlet in the side of a building for draining water.
Lexico
Given the position of the outlets, they appear to be drains; in other words 'scuppers'.
Scuppers would be the best suggestion.