Seems like it's not clear how much time involvement they're expecting? Mentors get a stipend of $500, and writers get $6000 for three months of work?
It's not much, particularly as this seems to be out of the holiday season (Sep-Nov) which makes it hard for students. That said, in much of the world $2k a month (ie $24k pro rata) is a reasonable salary for writing documentation. There are worse paying graduate jobs.