Comment 2 for bug 668991

> and suggests that they "Save as SVG", even if the format
> that the document was saved in was an SVG variant

Choosing a variant of SVG doesn't mean there is no risk of data loss: Formats like 'Plain SVG' and 'Optimized SVG' are seen as lossy formats compared to Inkscape's native format (Inkscape SVG(Z)) because they doesn't support Inkscape-specific extensions and attributes which e.g. allow to keep the document structured into layers, shapes parametrized and path effects editable and live-updating.