File descriptions:

 * GRCh38-f1g-90.gfa.gz: graph taking GRCh38 as the reference

   - reference: GRCh38
   - sample 1: CHM13
   - rest of haplotypes added in the lexicographical order of populations and then file names
   - no HG002, HG005 or NA19240 in the graph
   - 90 haplotypes in total including GRCh38 and CHM13
   - GRCh38-f1g-90.gfa.log shows the exact command line

 * CHM13-f1g-90.gfa.gz: graph taking CHM13v1Y as the reference

   - reference: CHM13v1Y
   - sample 1: GRCh38
   - rest of samples are the same as in GRCh38-f1g-90.gfa.gz

 * {GRCh38,CHM13}-f1g-90.bb.bed.gz: variation bubbles generated by `gfatools bubble`

   1. chromosome
   2. start
   3. end
   4. # GFA segments in the bubble including the source and the sink of the bubble
   5. # all possible paths through the bubble (not all paths present in input samples)
   6. 1 if the bubble involves an inversion; 0 otherwise
   7. length of the shortest path (i.e. allele) through the bubble
   8. length of the longest path/allele through the bubble
   9-11. obsolete fields
   12. list of segments in the bubble; first for the source and last for the sink
   13. sequence of the shortest path (* if zero length)
   14. sequence of the longest path (NB: it may not be present in the input samples)

 * {GRCh38,CHM13}-f1g-90.anno.bed.gz: crude annotations for the longest walk in
   each bubble. Generated by `minigraph/misc/mgutils.js anno` from
   RepeatMasker, lh3/minimap2/sdust, lh3/dna-brnn and lh3/etrf outputs.

   1-11. copied from *.bb.bed.gz
   12. annotations
     - most categories from RepeatMasker (e.g. SINE/Alu and LINE/L1)
     - inter: mixed interspersed repeat
     - alpha: alpha repeat
     - hsat2/3: hsat2 or hsat3
     - micro: microsatellite / STR (repeat unit <=6bp in length)
     - mini: low-complexity minisatellite / VNTR (repeat unit >6bp)
     - lcr: low-complexity regions but not clearly STR or VNTR
     - mixed: mixed interspearsed repeats and LCR repeats
     - partial: partially repeats (<70%); segmental duplications fall in this category
     - self: non-repetitive but have good hits to the reference genome
   13-. detailed annotations and their lengths