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Most of the packages use GitHub for hosting code.
A valid package directory structure
In the process of package installation,
Python's pip will run `./setup.py` from unpacked package dir.
this is kind of protocol between package developer and package manager.
In Julia, the package manager run `./deps/build.jl` from the git-cloned dir.
Here comes an issue of mxnet's main repo.
The Julia package is collected under the subdir `./julia/`, so the setup script
in our case is `./julia/deps/build.jl`.
This breaks the protocol.
Also, in runtime, there is another protocol for phase of module loading.
The entry point of a module must be `./src/PackageName.jl`.
In our repo, it's `./julia/src/MXNet.jl`.
So, the directory structure of mxnet main repo is invalid for Julia package manager.
Putting the url of main repo as package metadata will not work.