[nish__]

Can't you do it by hand pretty easily? It's a list of coordinates separated by spaces. For example: "100,100 100,200 200,200 200,100"

[amelius]

No, the specification is more complicated, for example elements (and sub-elements recursively) can have transforms applied to them.

[boothby]

Excellent point. Inkscape has (had?) a feature to simplify SVG files, which pushed transformations down the tree. I never needed to use this in an automated process, just the occasional file.