A selection of Gaia DR3 data in the broad vicinity of the Cr 135 and UBC 7. Cr 135, UBC 7, and their closest neighbouring clusters according to Cantat-Gaudin et al. (2020), left panel. Refined sample of 60% of the members of Cr 135 and UBC 7 over the same sky area, right panel. The colour-coding indicates the MP according to Eq. (1). The circles in both panels represent the half-number radii of the clusters according to Cantat-Gaudin et al. (2020). See discussion in the text.