I did not understand the objective of the Diagram (in contrast to the Gramps Data Model diagram) until exploring. Stating that outright might start a discussion of uses for the diagram. Gramps Data Model diagram (https://github.com/mod-by-cis/gramps-data-model) I shared it under Creative Commons Zero terms.
The graphs of the data model were created in the free yEd programme of the yWorks. yEd - live, yEd - downloads.
Unable to find a chart of the data model in Gramps anywhere, I decided to create one myself. I claim no rights to it—I just want to share it in case it might help someone.
IMHO showing all existing relations between the records is of little help in understanding the data model. Such a global drawing contains all potential links between records without explicitly telling in which circumstances these links are active.
I prefer to split the diagram into “local” diagrams related to primary interest records where only the links relevant to this record are depicted. See for example here the case of Person.
This is less confusing because it eliminates loops present in the global diagram.
One of the big differences in the new diagrams (shared by Jan… or Patrick in that thread) from the Gramps Data Diagram (shared by Nick in the wiki) is these new diagrams can easily be reshaped.
The object data is in a format for another drawing Application where boxes can be moved and the flow of arrows will recalculate.
gramps-6.0.0_MODEL_(eng).graphml
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.png ":inbox_tray:"){kind=small}
.jpg ":inbox_tray:"){kind=small}
.svg ":inbox_tray:"){kind=small}
.png ":inbox_tray:"){kind=small}
.jpg ":inbox_tray:"){kind=small}