This empty package does not provide any modules; its sole purpose is to provide the network-uri Cabal flag logic below so you don't have to include that boilerplate in your .cabal file.

flag network-uri
  description: Get Network.URI from the network-uri package
  default: True

library
  if flag(network-uri)
    build-depends: network-uri >= 2.6, network >= 2.6
  else
    build-depends: network-uri < 2.6, network < 2.6

This avoids combining network-uri >= 2.6 with network < 2.6 which both export a name-clashing Network.URI module, because in network-2.6 the Network.URI module was split off from the network package into network-uri-2.6.

In other words, the logic above makes sure that the Network.URI module is provided by either network-uri or by network (in the XOR sense).

In order to benefit from this module, simply include it in your build-depends declaration alongside network and network-uri.

  build-depends:
    network >= 2.5 && < 2.7,
    network-uri >= 2.5 && < 2.7,
    network-uri-flag == 0.1.*

NOTE: It's almost always an error to list this package if network and network-uri aren't both listed as well!