The "deconstruct" command:

Usage fossil deconstruct ?OPTIONS? DESTINATION

This command exports all artifacts of a given repository and writes all
artifacts to the file system.  The DESTINATION directory will be populated
with subdirectories AA and files AA/BBBBBBBBB.., where AABBBBBBBBB.. is the
40+ character artifact ID, AA the first 2 characters.
If -L|--prefixlength is given, the length (default 2) of the directory prefix
can be set to 0,1,..,9 characters.

Options:
  -R|--repository REPOSITORY  Deconstruct given REPOSITORY.
  -K|--keep-rid1              Save the filename of the artifact with RID=1 to
                              the file .rid1 in the DESTINATION directory.
  -L|--prefixlength N         Set the length of the names of the DESTINATION
                              subdirectories to N.
  --private                   Include private artifacts.
  -P|--keep-private           Save the list of private artifacts to the file
                              .private in the DESTINATION directory (implies
                              the --private option).

See also: reconstruct, rebuild