Where is the factory-reset image located on the bq Ubuntu phone

Question

The factory-reset option in system settings on the bq ubuntu phone reverts the phone back to factory settings. Where, on the phone, is the image located used by factory-reset to reset the phone?

Answer 1

As popey said:

[The factory-reset option] just deletes user data. It doesn't wind the clock back to the original factory image, so there isn't a factory image present on the device.