The square brackets are usually just used to give context from previous sentences / paragraphs that would not be obvious otherwise. So e.g. "He [James] paid hi

The square brackets are usually just used to give context from previous sentences / paragraphs that would not be obvious otherwise. So e.g. "He [James] paid him [John].". Where both names were in a previous paragraph. If we read the previous paragraph in the article that makes sense, because it was literally clarifying questions about the efficacy of using it for drug trafficking.