It needs to be extracted from the .fz file. Instructions for doing so are here:
In this case you are looking for logo in the Pico-breadboard.fz file which finds:
<instance moduleIdRef="newBreadboardLogoImageModuleID" modelIndex="85441645" path=":/resources/parts/core/newbreadboardlogoimage.fzp">
<property name="color" value="#787878"/>
<property name="width" value="35.3"/>
<property name="height" value="49.93322657653061"/>
<property name="shape" value="<?xml version='1.0' encoding='UTF-8' standalone='no'?> <!-- Created with Inkscape (http://www.inkscape.org/) --> <svg xmlns="http://www.w3.org/2000/svg" id="svg2798" width="1.38976in" viewBox="0 0 35.327335 49.971893&quo
The “shape” property contains the html encoded svg. The vi commands undo the html encoding to leave you with this svg. Here is one recovered svg (click on it and choose “save as” and you should get the svg):
It appears it wants the layerId (the group for the whole svg) to be breadboard (pcb wants boardoutline as I recall.) Other than that it is a normal svg. If you put this file name in to the load image file box in Fritzing it should load the svg in to a logo ready for use.
Peter