VPD analysis
There is no separate VPD chart in chat. Growi answers a VPD question like any other sensor question: “show my VPD” gives the normal line chart of the sensor, with an explanation in text. The chart has no target band, no peak time and no count of hours outside a band.
How it works
Section titled “How it works”LetsGrow has two VPD values, VPD plant and VPD greenhouse, both in kPa. In your data the sensors are named “Plant: VPD - kPa” and “Greenhouse: VPD - kPa”. The Glossary says what each one means.
A VPD question about your own crop needs a selected crop with a VPD sensor in one of its modules. Without a selected crop, Growi shows the crop card first. See Choosing a crop. When the chart appears and which period it covers is the same as for every sensor. See How Growi shows an answer.
A question about a target needs no data of your own. The start screen of the chat offers “What is the ideal VPD for tomatoes?” under the topic Climate. Target values come from the LetsGrow knowledge base. If it has nothing for your crop, Growi uses general horticultural knowledge and says that variety and growth stage can shift the optimum. Growi states which source it used. See Where Growi’s knowledge comes from.