KiraFermatPath is an option for
KiraRunReduction and other Kira-related functions.
It specifies the full path to the Fermat binary used by Kira to run
the reduction. This is done via the option KiraFermatPath.
The default value is Automatic meaning that suitable
binaries are expected to be located in
FileNameJoin[{$FeynHelpersDirectory, "ExternalTools", "Fermat"}]
Overview, KiraMassDimensions, KiraJobFileName, KiraIntegrals.