  This is the second paper in a series of studies of the Coma cluster using the
SRG/eROSITA X-ray data obtained during the calibration and performance
verification phase of the mission. Here, we focus on the region adjacent to the
radio source 1253+275 (radio relic, RR, hereafter). We show that the X-ray
surface brightness exhibits its steepest gradient at $\sim 79'$ ($\sim
2.2\,{\rm Mpc}\approx R_{200c}$), which is almost co-spatial to the outer edge
of the RR. As in the case of several other relics, the Mach number of the shock
derived from the X-ray surface brightness profile ($M_X\approx 1.9$) appears to
be lower than needed to explain the slope of the integrated radio spectrum in
the diffusive shock acceleration (DSA) model ($M_R\approx 3.5$) if the magnetic
field is uniform and the radiative losses are fast. However, the shock geometry
is plausibly much more complicated than a spherical wedge centered on the
cluster, given the non-trivial correlation between radio, X-ray, and SZ images.
While the complicated shock geometry alone might cause a negative bias in
$M_X$, we speculate on a few other possibilities that may affect the
$M_X$-$M_R$ relation, including the shock substructure that might be modified
by the presence of non-thermal filaments stretching across the shock and the
propagation of relativistic electrons along the non-thermal filaments with a
strong magnetic field. We also discuss the "history" of the radio galaxy
NGC4789, which is located ahead of the relic in the context of the Coma-NGC4839
merger scenario.
