help message for IndexBuilderMain

[pfps]

getafix /home/local/scripts> /home/local/qlever/qlever-code/build/IndexBuilderMain --help
Options for IndexBuilderMain:
...
  -f [ --kg-input-file ] arg            The file with the knowledge graph data 
                                        to be parsed from. If omitted, will 
                                        read from stdin.
  -F [ --file-format ] arg              The format of the input file with the 
                                        knowledge graph data. Must be one of 
                                        [nt|ttl|nq]. Can be specified once 
                                        (then all files use that format), or 
                                        once per file, or not at all (in that 
                                        case, the format is deduced from the 
                                        filename suffix if possible).

The description of -f appears to indicate only one input file is allowed but the description of -F appears to indicate that multiple input files are allowed. Which is the case?