Left panel: map of the Gaia DR3 proper motion components for member stars of UMi spectroscopically confirmed by Kirby et al. (2010), Pace et al. (2020) and Sestito et al. (2023). Sources are colour-coded according to their G magnitudes in the Gaia DR3 catalogue. Central panels: errors of the Gaia DR3 proper motion components plotted vs G magnitude for the sources in the left panel. The dashed lines show the 0.55 mas/yr threshold that we adopted to distinguish between reliable and less reliable proper motions. Right panel: Gaia DR3 proper motions of sources around UMi’s centre. The sources are colour-coded as in Figs. 2 and 5. In particular, the filled orange and red circles are RGB member stars of UMi with proper motion uncertainties smaller than 0.55 mas/yr. A lime cross marks the mean proper motions of the faint cluster Muñoz 1 according to Vasiliev & Baumgardt (2021).