Field of view observed with CRISP in the wing of Ca ii 8542 Å. Inset: detailed view of the line core in the region of interest. Yellow lines: fibrils selected for analysis. The yellow segments define the direction of the three-pixel wide bands used for Stokes Q and U profile averaging. Red cones: range of magnetic-field azimuth compatible with the Q and U profiles. The intensity scale has been saturated to enhance the contrast of fibrils. The tick-mark separation of the inset is 2″ covering an area of 39 × 38″ on the surface of the Sun.