Original sentence: GAL (an acronym for Grupos Antiterroristas de Liberación,  "Antiterrorist Liberation Groups") were death squads established illegally by officials of the Spanish government to fight ETA, the principal Basque separatist militant group
Edited sentence: GAL (an acronym for Grupos Antiterroristas de Liberación,  "Antiterrorist Liberation Groups") were death squads established illegally by officials of the Spanish government to fight ETA, the principal Basque separatist militant terrorist group