Galley diffs two versions of a typeface — or overlays up to four, each in its own colour — every outline, metric, kern pair and OpenType feature, and tells you what will reflow. All on your machine. Nothing uploads, ever.
Gchanged
G advance width 660 → 661 — running text set with the previous version may reflow.
G outline changed: 1 contour, 37 points moved.
Uppercase
Lowercase
Figures
Punctuation
Diacritics
Other
Gchanged
G advance width 660 → 661 — running text set with the previous version may reflow.