Such external debug info files are created by the dsymutil command.  Usually, it
creates a <name>.dSYM bundle directory but it can also produce a <name>.dwarf
flat file.  The code will find and use either.  It first checks if such a bundle
or file is adjacent to the module binary.  If it's not, it uses Spotlight to
search for a .dSYM bundle based on the binary's UUID, which is what gdb and lldb
do, too.  That way, it can find it anywhere on the system.