The root README has the timeline of all generations since 2009. Each generation folder explains its hardware and what is in it. .gitattributes turns off line-ending conversion so all files stay as they were.
Visual Studio build output (.obj, .pdb, .tlog, .sdf, .suo, ipch) of the 2012 IK visualiser and Unity's .vs, Logs and UserSettings of the 2018 simulation. They stay in the history. The built 'Hexapod app.exe' (Debug) is kept. Also drops the per-folder .gitattributes of the Processing sketch (the repo root now defines how files are stored) and the 2016 README of the old Hexapod repo (its only content was a GitLab link).