Pen trails can be exported as an SVG by right-clicking on the stage:

The "Pen Vectors" reporter block can also be used to report pen trails that have occurred since the last "Clear":

Is there a way to use the "Pen Vectors" reporter block to export the SVG file via a script (rather than by right-clicking on the stage)?
In the pixels library, there is an export costume block, that can be used to download the svg.
I don't think that exports the pen trails costume as an svg
[edit]Because the pen trails costume isn't an svg - Snap! has already turned it into a bitmap I think
I can never get the pen vectors reporter to work so
I just used "Export Costume [Pen Vectors]" and it worked like a charm!

Thanks so much!
It does export as svg, if you use the pen vectors block after enabling log pen vectors.
I'd just got to the same point when you all posted 