  Localization properties of fields in compact extra dimensions are crucial
ingredients for string model building, particularly in the framework of
orbifold compactifications. Realistic models often require a slight deviation
from the orbifold point, that can be analyzed using field theoretic methods
considering (singlet) fields with nontrivial vacuum expectation values. Some of
these fields correspond to blow-up modes that represent the resolution of
orbifold singularities. Improving on previous analyses we give here an explicit
example of the blow-up of a model from the heterotic Mini-landscape. An exact
identification of the blow-up modes at various fixed points and fixed tori with
orbifold twisted fields is given. We match the massless spectra and identify
the blow-up modes as non-universal axions of compactified string theory. We
stress the important role of the Green-Schwarz anomaly polynomial for the
description of the resolution of orbifold singularities.
