- --preferred-pack=<pack>
-  Optionally specify the tie-breaking pack used when multiple packs contain the same object. <pack>must contain at least one object. If not given, ties are broken in favor of the pack with the lowest mtime.
- --[no-]bitmap
-  Control whether or not a multi-pack bitmap is written. 
- --stdin-packs
-  Write a multi-pack index containing only the set of line-delimited pack index basenames provided over stdin. 
- --refs-snapshot=<path>
-  With --bitmap, optionally specify a file which contains a "refs snapshot" taken prior to repacking.A reference snapshot is composed of line-delimited OIDs corresponding to the reference tips, usually taken by git repackprior to generating a new pack. A line may optionally start with a+character to indicate that the reference which corresponds to that OID is "preferred" (see git-config[1]'spack.preferBitmapTips.)The file given at <path>is expected to be readable, and can contain duplicates. (If a given OID is given more than once, it is marked as preferred if at least one instance of it begins with the special+marker).