Google dug up the following (which didn't turn up when I searched maemo.org!)

http://forums.internettablettalk.com...4&postcount=34

Checking again, redshift requires xrandr >= 1.3, so that's a non-starter for the N900. I'll look and see what is possible with the xrandr-dev libs that come with the sdk - however I think we can call it a no-go for a redshift port.

In the meantime, a means of staggering the brightness across day might be a reasonable. Fbreader, even with white on black nearly burns the core of my retina when I'm reading late at night ... it's a PITA having to traverse the control panel just to change it