Someone Needed To Write A Custom Script For Gimp

Someone posted something interesting:

Hi, i want somebody's help who is able to write a script:

to get a palette of colors around my source input color:
.5 steps darker and 5 steps lighter,
.5 steps more saturated and 5 steps less saturated,
.5 steps brighter grey and 5 steps darker gray,


organized in tree blocks, divided by a black delimiter. The gradations
should fit into the available range of tonal values.

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