The repository has 2 SVG files:
This is a simple Flask-based web app that demonstrates using Fabric.js to implement a direct-manipulation SVG annotation tool. For documentation see the project's README.md, esp. the user documentation section. Briefly you can edit the annotation rectangles by creating ("+R") selecting, dragging, resizing, deleting ("-R" or Delete key), and nudging using tab/shift-tab, arrows (shift -> 10px, option -> resize instead of move). Link/unlink two rects of the same type using "+L" and "-L". Number keys 1-3 change the type of the next-to-create rect. Type 'x' to get the selected rect's simulated text.