The type attribute is a generic attribute and it has different meaning based on the context in which it's used.
For the <animateTransform> element, it defines the type of transformation, whose values change over time.
For the <feColorMatrix> element, it indicates the type of matrix operation. The keyword matrix indicates that a full 5x4 matrix of values will be provided. The other keywords represent convenience shortcuts to allow commonly used color operations to be performed without specifying a complete matrix.