  We classify the admissible transformations in a class of variable coefficient
Korteweg--de Vries equations. As a result, full description of the structure of
the equivalence groupoid of the class is given. The class under study is
partitioned into six disjoint normalized subclasses. The widest possible
equivalence group for each subclass is found which appears to be generalized
extended in five cases. Ways for improvement of transformational properties of
the subclasses are proposed using gaugings of arbitrary elements and mapping
between classes. The group classification of one of the subclasses is carried
out as an illustrative example.
