My favorite free (though not open source) visual diff and merge tool is Perforce's P4Merge. It's available for Linux, macOS (including as a Homebrew cask), and

My favorite free (though not open source) visual diff and merge tool is Perforce's P4Merge. It's available for Linux, macOS (including as a Homebrew cask), and Windows. My favorite feature is its conflict resolution listing the conflicting lines vertically in the source file (like diff3 conflict markers but a GUI) instead of side-by-side panes. https://www.perforce.com/products/helix-core-apps/merge-diff-tool-p4merge https://www.perforce.com/products/helix-core-apps/merge-diff...