When editing linestring geometries with the vertex tool, moving the mouse towards the first or the last vertex will display an extra marker just next to the endpoint. Clicking the marker will add a vertex at the end of the geometry.
This feature was funded by QWAT
This feature was developed by Martin Dobias (Lutra Consulting)
This application was created by Kartoza (Pty) Ltd. Available on GitHub! Version: 2.3.1