This is essentially a single string representation on where to get a package.

  npm://   webpack   @1.0.0
   |         |         |
provider    name    version

The only exception are http(s) links that can point to specific repo:package. When relevant, feel free to implemant repo-PRL in your own provider.

 http://  azukaar.github.io/GuPM-official/repo  :  provider-npm   @1.0.0
   |                      |                            |            |
provider              repo loc.                      name        version

Please note: only the package name is mandatory, all others parts are optionals.