Der entsprechende Eintrag im Changelog:

xap/fluxbox-1.0rc-i486-1.tgz:  Upgraded to fluxbox-1.0rc.
  I considered using --prefix=/usr here since X.Org will be moving from
  /usr/X11R6 to /usr when Slackware absorbs the modular release, but I
  think it will be best to wait and make those changes all at once.
  This, BTW, will be sometime after the 11.0 release.  This current to
  stable cycle has already taken too much time (10.2 is in need of
  replacement), and introducing changes that might break things at this
  point would be foolhardy.  Although there's still quite a bit in the
  TODO queue here I'm making my steps carefully as -current is very
  stable, and I think it should ship as a stable 11.0 soon so that we can
  get back to the business of breaking things in -current.  :-)