  One of the outstanding questions in the study of twisted bilayer graphene --
from both experimental and theoretical points of view -- is the nature of its
superconducting phase. In this work we perform a comprehensive synthesis of
existing experiments, and argue that experimental constraints are strong enough
to allow the structure of the superconducting order parameter to be nearly
uniquely determined. In particular, we argue that the order parameter is nodal,
and is formed from an admixture of spin-singlet and spin-triplet Cooper pairs.
This argument is made on phenomenological grounds, without committing to any
particular microscopic model of the superconductor. Existing data is
insufficient to determine the orbital parity of the order parameter, which
could be either p-wave or d-wave. We propose a way in which the measurement of
Andreev edge states can be used to distinguish between the two.
