Visual construction guides have been added to the advanced digitizing dock widget, which builds on the existing CAD construction mode.
When recording construction guides, QGIS will render all construction steps taken as dashed lines which will remain visible for as long as advanced digitizing is enabled. The guides are snap-able, allowing for construction steps to begin mid-way into a previous set of steps too.
The construction guides are stored in a vector layer, which is exposed through the advanced digitizing dock widget, allowing for further customization of the guides via other application processes, such as Python plugins.