  During its 2012 decline the R Coronae Borealis star (RCB) V854 Cen was
spectroscopically monitored with X-shooter on the ESO Very Large Telescope. The
obscured optical and near-infrared spectrum exhibits many narrow and several
broad emission features, as previously observed. The envelope is spatially
resolved along the slit and allows for a detailed study of the circumstellar
material. In this Letter we report on the properties of a number of
unidentified emission features (UFs), including the detection of a new one at
8692 {\AA}. These UFs have been observed in the Red Rectangle, but their
chemical and physical nature is still a mystery. The previously known UFs
behave similarly in the Red Rectangle and V854 Cen, but are not detected in six
other observed RCBs. Possibly the presence of some hydrogen is required for the
formation of their carrier(s). The $\lambda 8692$ UF is present in all RCBs.
Its carrier is likely of a carbonaceous molecular nature, presumably different
from that of the other UFs.
