How the comparison works
The tool computes a longest-common-subsequence diff over lines — the same core approach used by git and the Unix diff command. Unchanged lines are shown dimmed for context, removed lines in red with strikethrough, and added lines in green.
When to use a diff tool
Comparing config file versions, checking what changed between two drafts of a document, verifying a copy-paste didn't silently alter code, and reviewing changes when version control isn't available.