Change color intensity stroking along a path

[Ofnuts]

Very hard programmatically if is is a single stroke because there is no API in Gimp to set the fade length...

I don't know how OT's paths look but if they are a sequence of closed strokes, you can use my various scripts to

1) Decompose the path into individual strokes (ofn-path-edits(Break path apart))
2) Stroke each path with a color taken from a gradient (ofn-stroke-fill-paths )