turned out the issue was with the initial capitalisation of 'NickAger' so:
turned out the issue was with the initial capitalisation of 'NickAger' so:

"repository": "https://github.com/NickAger/elm-slider.git",

caused a javascript error for `--debug`, whereas:

"repository": "https://github.com/nickager/elm-slider.git",

works fine - who would have thought it!

NickAger/elm-slider,NickAger/elm-slider,NickAger/elm-slider,NickAger/elm-slider,NickAger/elm-slider