These are primarily in chests (apart from one guaranteed good food
item on the Mines branch level), and are quite likely to be potions
of healing, although other items that are useful for early-game
survivability are also possibilities.
This is part of a series of commits that aim to make the early game
less about waiting to heal up and more about pressing forwards. In
particular, this means that characters need likely access to
healing sources other than waiting/backtracking/hiding in closets.
In a future commit, I plan to make permafood generate primarily
through exploration (rather than drops from monsters) in order to
deter waiting around or grinding; the early guaranteed food drop is
present to give the more nutrition-intensive characters (e.g. orc
wizard or vegetarian Monk) a fair chance to reach the more abundant
food sources in Minetown or Sokoban.