  The dynamics of an asymmetric tracer in the symmetric simple exclusion
process (SEP) is mapped, in the continuous scaling limit, to the local current
through the origin in the zero-range process (ZRP) with a biased bond. This
allows us to study the hydrodynamics of the SEP with an asymmetric tracer with
a step initial condition, leading to the average displacement as a function of
the bias and the densities on both sides. We then derive the cumulant
generating function of the process in the high-density limit, by using the
Macroscopic Fluctuation Theory and obtain agreement with the microscopic
results of Poncet et al (2021). For more general initial conditions, we show
that the tracer variance in the high-density limit depends only on the
generalized susceptibility in the initial condition.
