I would call that an ANSI layout. But it isn't an off-shoot of the IBM Enhanced Keyboard layout.
It follows the keyboard layout for the DEC VT-220 terminal but changed into ANSI, and with more keys around the numeric keypad.
The VT220 (that came with the LK201 keyboard) was introduced in 1983, and elements its keyboard layout with its inverse-T arrow-key arrangement served as direct inspiration for IBM's Enhanced Keyboard (1985) layout that is the norm today.