CMD (left) and proper motion trends with Galactic longitude in μ_l (middle) and μ_b (right) of each structure. The CMDs contain the histogram of the stars within the highest intensity proper motion peaks (peak stars) with grey contours on top that represent the CMDs of all the stars in the region. The dashed black lines represent our selection of giant stars. The proper motion maps contain all the stars in the region, and the black line is the zero-contour of the peak stars, that is, the stars that fall within the highest intensity proper motion peak of their HEALpix. First row: MNC. Second row: bridge between MNC and the ACS. Third row: ACS. Fourth row: above the ACS. Fifth row: same region as the ACS but for the mock particles, selecting the stars for the CMD according to the contours of panels h and i. In the bottom panel we also include the proper motions expected from a structure 30° above the plane at a given distance – 4 (red) or 10 (orange) kpc – rotating at a given velocity – 200 (solid) or 220 (dashed) km s⁻¹ – but with no radial or vertical velocity.