The clone spell's components include, among other things (PHB, p. 222):
at least 1 cubic inch of flesh of the creature that is to be cloned
However, warforged do not have flesh as other humanoids do (E:RftLW, p. 35; WGtE, p. 67):
Warforged are made from wood and metal, [...]
And per the next paragraph:
Root-like cords infused with alchemical fluids serve as their muscles, wrapped around a framework of steel, darkwood, or stone.
This alone would seem to imply they cannot be targeted by the clone spell.
However, in the paragraph after that, their description also states:
Although they were manufactured, warforged are living humanoids. Resting, healing magic, and the Medicine skill all provide the same benefits to warforged that they do to other humanoids.
Would this list include the clone spell? I'm struggling to understand whether clone would be considered healing magic, and if an inch of the warforged's "flesh" would work here.
Can warforged be targeted by the clone spell?