SVG is an open vector format that virtually every graphics program can read. For sewing patterns it is the most flexible exchange format there is.
Curves as real Beziers, coordinates in millimetres, and separate objects for contour, grainline and marks. Because the format is text based and openly documented, an SVG written today will still open in twenty years, which is not something every proprietary pattern format can promise.
Illustrator, Inkscape and Affinity Designer all handle SVG, and Inkscape and Affinity cost nothing. Browsers display it, cutting plotters take it, and projection software reads it. That reach is the main reason to pick SVG when you are unsure.
For grading and production preparation, pattern CAD wants DXF, and CLO3D prefers PACX. SVG is the format for editing, printing and projecting, not the one for the industrial chain.
PatternScan Pro writes SVG with native Bezier curves, to scale in millimetres.

Digitize sewing patterns without tracing.
Test PatternScan Pro free for 14 days with the full feature set. You need your smartphone, a printer and one pattern you always wanted digital.