  Previous work (Pradines, 1966, Aof and Brown, 1992) has given a setting for a
holonomy Lie groupoid of a locally Lie groupoid. Here we develop analogous
2-dimensional notions starting from a locally Lie crossed module of groupoids.
This involves replacing the Ehresmann notion of a local smooth coadmissible
section of a groupoid by a local smooth coadmissible homotopy (or free
derivation) for the crossed module case. The development also has to use
corresponding notions for certain types of double groupoids. This leads to a
holonomy Lie groupoid rather than double groupoid, but one which involves the
2-dimensional information.
