"Er, is it the other way around? It looks like at least this post of mine came after the email discussion"
Yes, but the discussion started with the Arc topic and then moved to e-mail and then moved back to the Arc topic.
"I admit your approach handles the practical cases."
Well then! I'll consider that "all", since I only care about the practical cases.
"Your approach has developers hardcoding filenames within their source code. If a developer wants to use two files of the same name, they must find a way to segregate the files into subfolders, or they must rename a file and invade some library source code to rewrite the filename occurrences. Please let me know if I'm wrong about this. :)"
Yes. It is tied to the filesystem, or website URLs, or Git commits, or whatever. But, the filesystem already enforces a "no two files with the same name in the same folder" rule, so no biggie.
If you wanted to create something that manages dependencies at a more abstract level, that's fine, and you can build it on top of my system, but I personally don't see much use for that (yet).
If your worry isn't about filenames at all, and is simply about putting filenames into the source code, I think the answer is really easy: just do something like RubyGems, where you have a standard file called "dependencies" that imports all the dependencies in the right order. And then when you want to load the library, you'd just load the "dependencies" file. This doesn't require any changes to my system, since it's purely user-convention.
This still allows for putting the dependency information straight into the source code, which is useful for quickie scripts and such. But big projects and libraries would use the "dependencies" convention. And as Ruby showed, this kind of user-convention can be applied after the language is already in use. So it doesn't need to be baked in ahead of time, though there might be some minor transition pain. But I'll worry about that once libraries and projects become big enough that a "dependencies" convention becomes useful.