Yes, Tab. Exactly.

Which other diet sodas were identified as having "germs that love diet soda"?

The studies show effects for trehalose and saccharine. No diet soda contains trehalose, only Tab contains saccharine.

Any effect from the non-nutritive sweeteners in other diet sodas did not appear in the studies, so they focused on saccharine.

There may be more subtle effects from those sweeteners, or future effects from those sweeteners, but we haven't found them yet, extrapolation from a general principle not withstanding.

"Germs that love Tab" wouldn't draw as many clicks as the current title.