  The universal quantization of thermal conductance provides information on the
topological order of a state beyond electrical conductance. Such measurements
have become possible only recently, and have discovered, in particular, that
the value of the observed thermal conductance of the 5/2 state is not
consistent with either the Pfaffian or the anti-Pfaffian model, motivating
several theoretical articles. The analysis of the experiments has been made
complicated by the presence of counter-propagating edge channels arising from
edge reconstruction, an inevitable consequence of separating the dopant layer
from the GaAs quantum well. In particular, it has been found that the universal
quantization requires thermalization of downstream and upstream edge channels.
Here we measure the thermal conductance in hexagonal boron nitride encapsulated
graphene devices of sizes much smaller than the thermal relaxation length of
the edge states. We find the quantization of thermal conductance within 5%
accuracy for {\nu} = 1, 4/3, 2 and 6 plateaus and our results strongly suggest
the absence of edge reconstruction for fractional quantum Hall in graphene,
making it uniquely suitable for interference phenomena exploiting paths of
exotic quasiparticles along the edge.
