Absorption lines towards PKS 1830−211 observed with the Yebes 40 m telescope. The species identified for the first time in an extragalactic source are highlighted in red. The molecules highlighted in blue are those that were identified for the first time in this source, but observed previously in other extragalactic sources. The y-axis is the normalised intensity to the total (NE + SW) continuum level (see Sect. 3). We assume a z = 0.885875 (v₀ = 0 km s⁻¹ in the local standard of rest).