Where to find it:

NodeGraph / Right Mouse Click / Add Nodes / Math / Extension Pack / F /

fract returns the fractional part of x. This is calculated as x - floor(x).

https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/fract.xhtml

•X

Specify the value to evaluate.

•Output RGB

Separate computation for Input Channels Red, Green, Blue with an Alpha Channel of 1.0

•R

Computation for Input Red channel only, saved into R, G and B channel with an Alpha of 1.0

•G

Computation for Input Green channel only, saved into R, G and B channel with an Alpha of 1.0

•B

Computation for Input Blue channel only, saved into R, G and B channel with an Alpha of 1.0

•A

Computation for Input Alpha channel only, saved into R, G and B channel with an Alpha of 1.0