meldmerge.org
Meld is a visual diff and merge tool that helps compare files, directories, and version controlled projects. It provides two- and three-way comparison of files and directories, assists with three-way merges and conflict handling, and supports version control systems including Git, Mercurial, Bazaar and Subversion. It is packaged for most Linux/Unix distributions and available on Flathub; macOS is not yet supported.