The author is developing a theory of expressions (generalizations of list comprehensions) operating on 'ringads', which are monads with a few additional operations and laws.

The academic style probably blurs the fact that this has very deep practical applications, as it provides a framework that permits to write down database joins and OLAP multidimensional queries (including aggregation) in multiple ways that can be considered equivalent through application of monad and ringad laws. This in turn can enable us to interpret such expressions efficiently, by picking the one that corresponds to a desirable execution plan.

Another paper that I would consider related is the one that points out how comprehension expressions can express SQL features like 'order by' and 'group by', namely 'Comprehensive comprehensions' by Wadler and Peyton-Jones.