draw.io 22.214.171.124 adds a special field called “placeholder” in the metadata of cells. Setting “placeholder” as the key inserts the associated value as a global key with the cell label as the value. Take a look at this example diagram (click on it to open in draw.io):
The upper and lower “John Doe” labels are defining a global variable called “author”. Editing either label will change the other, since they share the same placeholder value. Selecting a cell and pressing ctrl+M opens the metadata dialog.
The paragraph starting “This diagram was…” is referencing the placeholder fields in the uppermost cell. Changing the labels in the top cell changes the cell below that references it, but not vice versa.
Previously, variables and referencing variables was more focused on group hierarchies of cells, this mechanism allows more flexibility.