  We provide new examples of curves of genus 6 or 10 attaining the Serre bound.
They all belong to the family of sextics introduced in [19] as a a
generalization of the Wiman sextics [36] and Edge sextics [9]. Our approach is
based on a theorem by Kani and Rosen which allows, under certain assumptions,
to fully decompose the Jacobian of the curve. With our investigation we are
able to update several entries in \url{http://www.manypoints.org} ([35]).
