I now installed the Add-On and it placed for me to the File\File Special location in the menu.
By the way, when installed, you should list the available command by the "All commands by theme" option, and under "17 Add-Ons" you will find the "3D Studio In" folder.
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2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac28