`$FeynHelpersDirectory specifies the location of FeynHelpers.
$FeynHelpersDirectory
Overview.
/home/vs/.Mathematica/Applications/FeynCalc/AddOns/FeynHelpers\text{/home/vs/.Mathematica/Applications/FeynCalc/AddOns/FeynHelpers}/home/vs/.Mathematica/Applications/FeynCalc/AddOns/FeynHelpers