Output and viewing
The library does not override your output format. Choose one the standard Asymptote way:
settings.outformat = "svg"; // or "pdf", "eps", "png"
asy mydiagram.asy # uses your configured format
asy -f svg mydiagram.asy # force SVG
Tip: if you rasterize the SVG output to PNG to preview it, use a WebKit-based tool (e.g. qlmanage on macOS) or a browser. ImageMagick does not resolve the glyph references in Asymptote’s SVG and will drop characters, making a correct figure look broken.