In notepad++, from the customui 88 SubdivTtools js file, I was able to cut out the base64 code, ( All of the code from just after ...base64, on down to just before " command="_Subdiv_beta9" ,
and paste it to the onle site:
https://codebeautify.org/base64-to-image-converter
and then download a jpg image.

I suppose an icon editor program could then make an icon,
but I do not know much about all of this.

What is a good, free, icon creator program?

- Brian