C provides two scopes for functions: Global to the entire program, and local to a file. When Dennis Ritchie designed C, memory capacities were measured in kilobytes and disk capacities in megabytes; a two-level namespace hierarchy was quite sufficient.
Today vanilla home systems have memory capacities measured in gigabytes, commodity disks have capacities on the order of terabytes, and software engineers need sophisticated namespace management facilities to tame the complexity dragon.
Each Mythryl software package lives in its own namespace; it may refer to the contents of other packages retail as foo::bar, or may import them wholesale as include package foo;. It may also incorporate other packages as sub-elements, and may protect selected components from direct external access by strong sealing with an appropriate API definition.