Used to specify a local search that is outside major markets.
lang:pt AND (altloc:br OR loc:br)
pt-us typically gets indexed as lang:pt loc:us, but in this example it would get indexed as lang:pt loc:us altloc:br altloc:pt. The altloc: locations are derived from major markets for the given language (pt-br and pt-pt in the case of this example). For more information about language codes, see Bing API Documentation.