The value was superior to mathematical Pi (as is best float approximation, but not best double approximation), such as having 2*PI normalized into [0,2*Pi] by standard trigonometric functions (which use accurate approximations of Pi) would not preserve it and yield a value close to 4.2e-10, which could cause suprises (for example if angular ranges are defined as (start,end) and not (start,span)).
https://media.ccc.de/v/mch2022-236-non-euclidean-doom-what-h...