There is one significant undocumented feature.   I now create streams based
on L2 filters as well as omni_filter output.  The filter based streams are
in the directory  D0$DATA$D0DAD$TRIGFILT, and the file names are of the form
RUN1B_FILT_filtername.D0DADF for the first pass reco and
RUN1B_D0FIX_FILT_filtername.D0DADF (challenge only).   The string 'filtername'
should be replaced by whichever L2 filter you want, e.g.,
RUN1B_FILT_MU_JET_HIGH.D0DADF.