Positional uncertainty and source density distribution in Gaia-CRF3. Left: histogram of the positional uncertainty σ_pos,max for Gaia-CRF3 sources with five-parameter solutions (blue) and six-parameter solutions (magenta). Middle: scatter plot of σ_pos,max versus the G magnitude. The dashed curve is the smoothed median uncertainty versus magnitude. The green points are the sources matched to ICRF3 S/X. Right: fraction of sky covered by a given minimum density of Gaia-CRF3 sources at different levels of positional uncertainty (see text for further explanation).