How to infer imported method names from IOS Mach-O binary

Question

When using a disassembler to analyze IOS binaries (Mach-O) files, I see that method names are annotated for functions in external libraries, even for C-style function calls in release binaries. I have been reading up on the Mach-O file format but am having trouble finding out to match up up the __stub_helper entries with the function names, and the names don't appear to be stored in the binary itself.

Thanks!