  We experimentally investigate Andreev transport through the interface between
an indium superconductor and the edge of the InAs/GaSb bilayer. To cover all
possible regimes of InAs/GaSb spectrum, we study samples with 10 nm, 12 nm, and
14 nm thick InAs quantum wells. For the trivial case of a direct band insulator
in 10~nm samples, differential resistance demonstrates standard Andreev
reflection. For InAs/GaSb structures with band inversion (12~nm and 14 nm
samples), we observe distinct low-energy structures, which we regard as direct
evidence for the proximity-induced superconductivity within the
current-carrying edge state. For 14~nm InAs well samples, we additionally
observe mesoscopic-like resistance fluctuations, which are subjected to
threshold suppression in low magnetic fields.
