> enabling developers to easily assign their own allocators

Through a combination of Zig's convention to pass around allocators instead of using a global allocator, the allocator interface's ability to return errors, and the Zig language forcing you to handle all errors (unless you explicitly discard them), a lot of Zig code is written with allocation failure in mind.

This means that you can seamlessly pass a custom allocator, say a bump allocator backed by a fixed buffer, to a function in some third-party library and still handle the case where the buffer runs out of space.

I did a quick search but didn't find anything substantial.