`araxis`;;           Use Araxis Merge (requires a graphical session)
`bc`;;               Use Beyond Compare (requires a graphical session)
`bc3`;;              Use Beyond Compare (requires a graphical session)
`bc4`;;              Use Beyond Compare (requires a graphical session)
`codecompare`;;      Use Code Compare (requires a graphical session)
`deltawalker`;;      Use DeltaWalker (requires a graphical session)
`diffmerge`;;        Use DiffMerge (requires a graphical session)
`diffuse`;;          Use Diffuse (requires a graphical session)
`ecmerge`;;          Use ECMerge (requires a graphical session)
`emerge`;;           Use Emacs' Emerge
`examdiff`;;         Use ExamDiff Pro (requires a graphical session)
`guiffy`;;           Use Guiffy's Diff Tool (requires a graphical session)
`gvimdiff`;;         Use gVim (requires a graphical session) with a custom layout (see `git help mergetool`'s `BACKEND SPECIFIC HINTS` section)
`gvimdiff1`;;        Use gVim (requires a graphical session) with a 2 panes layout (LOCAL and REMOTE)
`gvimdiff2`;;        Use gVim (requires a graphical session) with a 3 panes layout (LOCAL, MERGED and REMOTE)
`gvimdiff3`;;        Use gVim (requires a graphical session) where only the MERGED file is shown
`kdiff3`;;           Use KDiff3 (requires a graphical session)
`meld`;;             Use Meld (requires a graphical session) with optional `auto merge` (see `git help mergetool`'s `CONFIGURATION` section)
`nvimdiff`;;         Use Neovim with a custom layout (see `git help mergetool`'s `BACKEND SPECIFIC HINTS` section)
`nvimdiff1`;;        Use Neovim with a 2 panes layout (LOCAL and REMOTE)
`nvimdiff2`;;        Use Neovim with a 3 panes layout (LOCAL, MERGED and REMOTE)
`nvimdiff3`;;        Use Neovim where only the MERGED file is shown
`opendiff`;;         Use FileMerge (requires a graphical session)
`p4merge`;;          Use HelixCore P4Merge (requires a graphical session)
`smerge`;;           Use Sublime Merge (requires a graphical session)
`tkdiff`;;           Use TkDiff (requires a graphical session)
`tortoisemerge`;;    Use TortoiseMerge (requires a graphical session)
`vimdiff`;;          Use Vim with a custom layout (see `git help mergetool`'s `BACKEND SPECIFIC HINTS` section)
`vimdiff1`;;         Use Vim with a 2 panes layout (LOCAL and REMOTE)
`vimdiff2`;;         Use Vim with a 3 panes layout (LOCAL, MERGED and REMOTE)
`vimdiff3`;;         Use Vim where only the MERGED file is shown
`winmerge`;;         Use WinMerge (requires a graphical session)
`xxdiff`;;           Use xxdiff (requires a graphical session)