Written for FreeCAD 0.19
The Arch Reinforcement Bar adds Re-Bar to a selected face, for use within the Arch Workbench. The Re-Bar tool is tightly integrated to Arch but it is in fact a distinct entity
This article covers the RE-Bar tool added via the Add-On manager
The tool that comes prepackaged with FreeCAD ( at the time of publishing ) has a smaller set of tools.
The difference is easily distinguished if, on your, Arch workbench you see the 3 bar single icon, you have the default version.
The single icon, with the Add-On version is replaced with a pull-down and the following options.