AECnews.com has reported: There’s a Redlining Easter Egg in Autodesk DWFit.
Redlining is under development. It's hidden in Project Freewheel in pseudo Easter Egg form, because it is not ready yet. Having it in there allows us to test it in its live environment. Hiding it prevents premature exposure for something that is in the conceptual stage. The implementation concept was first envisioned by Programmer/Software Engineer Jeffrey Klug.
At this point in its development, I am opposed to the laying down of rules or conditions to be observed in the redlining of DWF files via Freewheel lest the progress of improvement tomorrow might be embarrassed or shackled by recording or registering as law the prejudices or errors of today. :-)
The initial markup experiment is limited to freehand sketching, for example no text, and does not provide the ability to save your markups. This is another reason its implementation is somewhat hidden.
P.S. The markup has since been removed. For the latest information on Project Freewheel, see Scott Sheppard's It's Alive in the Lab blog.