Punctuation question - why enclose these words in brackets?

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From an online article. Why enclose these words in brackets?



“[They’d] been [there] seven days a week, working extended tours and overtime and using all these resources, and it came down to a heads up surveillance member, with a picture, looking up … spotting this suspect,” said Rankin.

 

[Bugenhagen]

The words were not spoken aloud or were indistinct so inserted for clarity.

 

[Overnight]

The words were not spoken aloud or were indistinct so inserted for clarity.

Indeed. That is an editor deal. They are directly quoting someone, but have to do the bracket deal when the context is not clarified in the quote. It helps the reader make sense of said context.