The file c:File:Indifference curves showing budget line.svg has black blobs where it should not. Compare with the raw file at upload.
Seems like this also happen in the thumbnailer for Ubuntu.
This file is using an external namespace while styling the figure.
This is weird…
The SVG file has a large data URL in a style node which seems to be unused. I uploaded a version of the file without this element, but still the thumbnail won't render as it should.
Fixed the file, seems like the thumbnailer had problems with class declaration. The file also had additional problems.