It's not defined anywhere explicitly in studio and is usually defined on report level. You can check if you have defined it in studio. Go to Window -> Preferences -> Jaspersoft Studio -> Properties. Search for net.sf.jasperreports.governor.max.pages and net.sf.jasperreports.governor.max.pages.enabled.
Report level. Select report object, go to Properties tab -> Advanced tab -> Edit report properties. Search for these governors there.