Analysis and geometry on infinite-dimensional spaces is an active research field with many applications in mathematics and physics. Examples for appli cations arise naturally even when one is interested in problems that on first sight seem genuinely finite dimensional. You might have heard that it is im possible to accurately predict the weather over a long time. It turns out that this can be explained by studying the curvature of certain infinite-dimensional manifolds (Arnold, 1966). This example shows that everyday phenomena are intricately linked to geometric objects residing on infinite-dimensional man ifolds. In recent years the list of novel applications for infinite-dimensional (differential) geometry has broadened considerably. Among the more surpris ing novelties are applications in stochastic and rough analysis (rough path the ory à la T. Lyons leads to spaces of paths in infinite-dimensional groups; see Friz and Hairer, 2020) and renormalisation of stochastic partial differential equations via Hairer’s regularity structures (see Bogfjellmo and Schmeding, 2018).