Return each feature’s derived bounds, one row per feature.
Rows follow iteration order: the features table’s, then lone rows. Columns are feature_id (blank for a lone row), annotation (a lone row’s index label), kind, then <dim>_min and <dim>_max per dimension, blank where the feature spans it (NaT where the set states a time somewhere along that dimension, NaN otherwise); numbers are floats. A group’s bounds envelope its members’, a path’s or polygon’s its vertices, and a path drawn only from its basis its curve, exactly. A range row’s maximum is excluded, as its half-open range says; a value’s is included, and a value alone gives equal minimum and maximum: a point.