A pseudo-node is an unnecessary node in a geometric link that is shared by only two objects. For example, a long link might be divided unnecessarily into many, smaller links by pseudo-nodes.
Using the Dissolve Pseudo-Nodes cleanup action, you can locate any pseudo-nodes, dissolve the node, and join the two objects. This option removes nodes that are at the intersection of two linear objects, but leaves the vertex in place.
Pseudo-nodes exist where two links meet; removing them creates a single polyline on one layer.
When you dissolve a pseudo node on a 2D polyline with different Z values, the first Z-value on the object is used. On a 3D polyline, the Z-value on the first vertex is used. The object remains a 3D polyline. For all other properties, the values on the first object are used.