Notes (in five parts: 1, 2, 3, 4, 5), slightly expanded from those below, from a set of talks at the e-GeMAT seminar, also following the same preprint of T. Watanabe. (June/July 2020)

Notes (in four parts: 1, 2, 3, 4) from a set of talks at a reading seminar at Oxford on Kontsevich characteristic classes of 4-dimensional disc bundles, following a recent preprint (arxiv:1812.02448) of T. Watanabe. (May/June 2020)

A brief note on Assertion 6 in Milnor's book on the h-cobordism theorem, which arose during a seminar that I organised in the summer semester 2018 in Bonn. (June 2018)