Tim Mann has been responsible for XBoard versions 1.3 and beyond, and for WinBoard, a port of XBoard to Microsoft Win32 (Windows NT and Windows 95). H.G.Muller is responsible for version 4.3.
Mark Williams contributed the initial (WinBoard-only) implementation of many new features added to both XBoard and WinBoard in version 4.1.0, including copy/paste, premove, icsAlarm, autoFlipView, training mode, auto raise, and blindfold. Ben Nye contributed X copy/paste code for XBoard.
Hugh Fisher added animated piece movement to XBoard, and Henrik Gram
(henrikg@funcom.com) added it to WinBoard. Frank McIngvale added
click/click moving, the Analysis modes, piece flashing, ZIICS import,
and ICS text colorization to XBoard. Jochen Wiedmann ported XBoard to
the Amiga, creating AmyBoard, and converted the documentation to
texinfo. Elmar Bartel contributed the new piece bitmaps introduced in
version 3.2. John Chanak contributed the initial implementation of
ICS mode. The color scheme and the old 80x80 piece bitmaps were taken
from Wayne Christopher's XChess program.
Chris Sears and Dan Sears wrote the original XBoard. They were responsible for versions 1.0 through 1.2.
Evan Welsh wrote CMail. Patrick Surry helped in designing,
testing, and documenting CMail.
Alessandro Scotti added many elements to the user interface of WinBoard, including the board textures and font-based rendering, the evaluation-graph, move-history and engine-output window. He was also responsible for adding the UCI support.
H.G. Muller made WinBoard castling- and e.p.-aware, added variant support with adjustable board sizes, the crazyhouse holdings, and the fairy pieces. In addition he added most of the adjudication options, made WinBoard more robust in dealing with buggy and crashing engines, and extended time control with a time-odds and node-count-based modes. Most of the options that initially were WinBoard only have now been back-ported to XBoard.
Michel van den Bergh provided the code for reading Polyglot opening books.
Arun Persaud worked with H.G. Muller to combine all the features of the never-released WinBoard 4.2.8 of the Savannah project (mainly by Daniel Mehrmann), and the never-released 4.3.16 into a unified WinBoard 4.4, which is now available both from the Savannah web site and the WinBoard forum.