Leaf nodes of the tree contain metadata describing the data associated to the node.
This specification makes a distinction between signals - in the following as sensor, actuator and stream - and attribute.
The difference between a signal and an attribute is that the signal has
a publisher (or producer) that continuously updates the signal value while an
attribute has a set value, defined in the specification, that never changes.
As summary, besides branch type can be:
attribute, which describes static read-only value.sensor, which describes non-static read-only signal.actuator, which describes a non-static read-write signal.stream, data stream like video.Examples you’ll find in the sensor and actuator chapter.