There is a report from Purdue University online that the unripe fruit of Carica pubescens is boiled or roasted in the Andes and eaten as a vegetable (1). I tried boiling some small very unripe green fruit. After ten minutes they were intensely bitter and were a bit too firm. After 1 and 2 hours of boiling the bitterness was reduced considerably and the texture was much softer and better, but I still found them too bitter to be enjoyable.
It seems likely either the locals resort to it only when they are desperate or they have acquired a taste for the bitterness, which is very unusual with food but not unheard of. It is also possible they are normally cooked for extremely long periods, for days perhaps by fire, but not very likely. It also seems possible the report is inaccurate, although this would be surprising coming from Purdue, possibly it was confused with the more widely reported use of unripe Carica papaya fruit as a vegetable.
A New Zealand nursery also says the unripe fruit of the mountain pawpaw-babaco cross "rainbow valley" can be eaten as a vegetable but it is also bitter.
1. https://hort.purdue.edu/newcrop/1492/fruits.html
