Their website makes their definition of portable very clear in "What makes a portable app special?".
It's quite clear they mean more a (much) stricter variation of the "no installation" definition than the "easily buildable on other OS" definition. Though they do mention execution under translation environments as a requirement.
It's quite clear they mean more a (much) stricter variation of the "no installation" definition than the "easily buildable on other OS" definition. Though they do mention execution under translation environments as a requirement.