SDSS i-band image extracted from the final MUSE datacube for the same field-of-view shown in Fig. 3. We indicate the position of QSO1, QSO2 and of a faint galaxy unveiled in projection between the targeted quasar pair. This galaxy is an interloper at a different redshift, tentatively at z = 0.457 ± 0.001 (Appendix B and Fig. B.2). For comparison purposes, we also show the 2σ isophote for the extended Lyα emission (black). To guide the eye we overlay a grid spaced by 10″ (or 77 kpc), as done in Fig. 3.