  We present the notion of non-abelian descent type, which classifies torsors
up to twisting by a Galois cocycle. This relies on the previous construction of
kernels and non-abelian Galois 2-cohomology due to Springer and Borovoi. The
necessity of descent types arises in the context of the descent theory where no
torsors are given a priori, for example, when we wish to study the arithmetic
properties such as the Brauer--Manin obstruction to the Hasse principle on
homogeneous spaces without rational points. This new definition also unifies
the types by Colliot-Th\'el\`ene--Sansuc, the extended types by
Harari--Skorobogatov, and the finite descent type by Harpaz--Wittenberg.
