VMD is available for macOS, Windows, Linux.
(as of 5/23/23) In VMD 1.9.4, Extensions -> Analysis -> RMSD Visualizer Tool will open, but only a portion of the RMSD Visualizer Tool window will be visible, making the tool unusable.
The RMSD Visualizer Tool works in VMD 1.9.3, which is only available for Windows computers and will not run on a modern macOS.
macOS labs at Carleton are running 1.9.4
Windows labs at Carleton are running 1.9.3