Pebre is a Chilean condiment made of coriander, chopped onion, olive oil, garlic and ground or pureed spicy aji peppers. Pebre is most commonly spooned on meat, usually from a barbecue. If you add chopped tomatoes it is called chancho en piedra. It is also used on bread, in lieu of butter, for example on a choripán. In far northern Chile it is used to name a sauce more like Bolivian llajwa.
In Brazil, a similar sauce can be found by the name of Vinagrete (which is less hot than Pebre due to the lack of peppers in it). This sauce is one of the most popular sauces in Brazilian churrascadas.
The word pebre in Catalan means pepper of any type, in this case ají cultivars of chilli pepper. The origin of Pebre as a sauce in Chile dates to the arrival of Catalan engineers and highly skilled masons under the supervision of the Italian architect Joaquin Toesca, for the construction of the Tajamares de Santiago, the fluvial channels, river walls and bridges for the main river that intersects the city of Santiago, the Rio Mapocho (Mapocho River). Catalan workers made a simple sauce (salsa) with cilantro, oil, vinegar and salt, called Pebre for its main ingredient the ají. Probably due to the lack of ingredients like pine nuts and roasted almonds this could be a variation of the Romesco sauce, a Catalan bell pepper sauce.
^Word taken from catalán (1555) "pebre", thus from Latinpiper, -eris - Coromines, Breve diccionario etimológico de la lengua Castellana ISBN 978-84-249-1332-8