Fork
After downloading and moving Kaleidoscope into the Application folder, you are ready to configure it to work with Fork. First you need to navigate to the Integration section in the Welcome Window.
The ksdiff tool can now be setup by clicking the "Install Now" button.
In Fork, choose Fork > Settings…
Navigate to the Integrations section. Select Kaleidoscope4 as Merge Tool and External Diff Tool.
And that's it, you're all set to start using Kaleidoscope together with Fork.