Compare this to Bangkok, where donations of leftover food are left on the street, but in those cases meant for the animals (dogs, cats, birds, etc.) who are believed to be reanimated friends, relatives, and fellow Bangkok-ers.
This appears to be charity with a slightly different target, leaving out bread for whoever finds it first – whether humans, crows, or otherwise. Based on how it has been left, these pieces of bread would stand out in a particular way by being first visible to someone headed to either dispose of garbage or search for sustenance. The risk with this, of course, is how that same level of visibility raises the stakes for actually taking the food – if one is sensitive about revealing their lack of resources through searching for food on the street, it would be difficult to grab this bread without anyone else noticing.
Consider the charity infrastructure – whether formal or informal – in your own neighborhood, and in particular around food. How “visible”of an activity is partaking in charity where you are? Here in Boston, I live not far from the a large public park in central Boston, the Commons, walking home after nightfall I sometimes see a van from a local church pulled up on to a small pavilion in a park, and people lined up to be distributed a package of donated food out of the back.