A diff highlights added and removed lines, but its quality depends on what you compare. Put the known old version beside the proposed new version in the diff checker. Review each changed hunk with surrounding context, then scan the final document for inconsistencies a line-level view can miss.
If the output is noisy, check line endings, indentation, and generated timestamps. Normalize only differences that truly do not matter; whitespace can be meaningful in code or data. For JSON, a structural diff may be better than a text diff, especially when object keys moved. Keep confidential text in a trusted local tool instead of pasting it into an unknown service.
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