Most stuff in extras-devel is for the N800 and N810. Developers can select Fremantle additional to Diablo and Chinook when uploading stuff. Many people did so while uploading for Diablo and Chinook to see if their package passes the autobuilder for Fremantle. These applications were never meant to actually be run on the real device, and some will even fail, e.g. usbcontrol.

@Florob:
Yes, the place is /opt. Actually it's /home/opt on the /home partition with /opt being a link to /home/opt. Packages should install into /opt.
What I personally don't like it that the optification process scatters symlinks to the /opt stuff all across the / partition. But this is the only way to optify unrelocatable software.