  We continue the study of the representation theory of a regular weak
multiplier bialgebra with full comultiplication, started in arXiv:1306.1466,
arXiv:1311.2730. Yetter-Drinfeld modules are defined as modules and comodules,
with compatibility conditions that are equivalent to a canonical object being
(weakly) central in the category of modules, and equivalent also to another
canonical object being (weakly) central in the category of comodules.
Yetter-Drinfeld modules are shown to constitute a monoidal category via the
(co)module tensor product over the base (co)algebra. Finite dimensional
Yetter-Drinfeld modules over a regular weak multiplier Hopf algebra with full
comultiplication are shown to possess duals in this monoidal category.
