To download a build: Go to the Jobs section. It is currently set up to make builds of the master branch only (will eventually become GIMP 3.0). Gitlab CI for GIMP now has a job building GIMP for Windows.
The disk-image file includes an OS X installer package, an uninstaller package, plus illustrated documentation to easily guide you through the printer set-up process. Gimp-Print 4.2.7 is the last stable release of Gimp-Print version 4.2.x for Mac OS X it includes 225 drivers supporting over 600 printers.
