The current Blender manual gives this illustration as a use-case for the Capture Attribute node:
Can anyone make this work? There is nowhere on the modified curve to store the output attribute, on points which don't exist before GN modification. If I create one with an arbitrary name in the 'Output Attributes', I can't seem to pick it up in a shader Attribute input node.
It would seem odd to publish an example in the manual which can't be reproduced.