I would agree, likely nothing will change. I don’t think the issue is in Inkscape but rather in Fritzing.
You look to be correct, I got a wrong svg in the initial look. This is the breadboard svg from your .fzpz file. Note the linear gradient doesn’t render in Inkscape
This is your original svg where the linear gradient does render in Inkscape
the problem appears to be in the style definitions for path871, in the svg from your .fzpz file the filter:url(#filter1015-5) element is missing in both the style and in the inline xml. Presumably that is why the path doesn’t render. It seems Fritzing deleted that when it processed the svg to write to the .fzpz file and that causes path871 to not render (in both Fritzing and Inkscape!)
Yes, it appears to me that Fritzing (or more likely QT) can’t render the blur. This is the breadboard view in Fritzing of the corrected .fzpz file:
this is the same svg displayed in Inkscape. The blur appears in Inkscape but not in Fritzing, indicating to me that Fritzing does not support the blur function and there likely isn’t anything that can be done about that.
the blur is not appearing in Fritzing likely meaning it can’t render it.
Peter