The cage was labelled for Indochinese Black Langur (T. ebenus) and did hold one individual of that species, but also three Francois' Langurs and this hybrid langur which at the time I thought was a Laotian Langur but is actually a wild hybrid between Francois' and White-headed Langur. It was very difficult to get proper photos because the glass was both dirty and very reflective in the sun.
@Himimomi it can't be a White-headed Langur - the head colour, limb colour, and tail colour are all wrong. On the other photo @Ding Lingwei suggests it is a hybrid White-headed X Francois' which makes more sense.
