The "import" command:
Usage: fossil import --git ?OPTIONS? NEW-REPOSITORY
Read text generated by the git-fast-export command and use it to
construct a new Fossil repository named by the NEW-REPOSITORY
argument. The git-fast-export text is read from standard input.
The git-fast-export file format is currently the only VCS interchange
format that is understood, though other interchange formats may be added
in the future.
The --incremental option allows an existing repository to be extended
with new content.
--incremental allow importing into an existing repository
See also: export