jhbuild is installed in ~/Source, and produces a binary which appears in ~/bin. jhbuild then puts everything it is building in ~/gtk (controlled by the .jhbuildrc hidden file). ~/gtk/source contains the downloaded sources, and ~/gtk/inst contains the built libraries and applications. More is built than is needed in the final GRAMPS application - for example, the build tools are themselves built. jhbuild gets its instructions on how to build things from the file ~/gramps_important_info/gramps.modules. This large file includes all the instructions to build all the libraries as well as GRAMPS itself, to avoid relying on jhbuild's own instructions, which might change with time and change a build of GRAMPS unexpectedly. The intent is that each major release of GRAMPS ported to Mac will see this gramps.modules file revisited to update build instructions for libraries to the latest stable releases.

build_gramps goes on to produce an application package on the desktop. It does this just by copying the relevant files, and creating some symbolic links in the target. The files come either from ~/gtk/inst, or from ~/gramps_important_info. It's a fairly ad hoc procedure. It's possible some critical Python file or compiled C library is missed out of the application and will only be discovered later. This is to reduce the download size.