Begin / End curve ?

 From:  Frenchy Pilou (PILOU)
We have End snap, but not Start snap of a curve
That is curious because we can flip it so curve have an inverse way of direction
Useful when we must know what curves flip for avoid twist between them or other thing
A curve has alway a first point and last point at its creation, so a start and a end
except case of cmose curve of course :)