What is the name of this brown fruit from India?
This is NOT Sapodilla. Manilkara Zapota (chikoo) has different type of leaves. Manilkara doesn’t have three veined leaves, but one in the middle like on this pic:
The leaf in your image is typical Strychnos. More likely it is Strychnos nux-vomica, or Strychnine tree. It is the source of the poison strychnine.