How to activate GUI->xterm.js in a debian 12 VM?

In order to make xterm.js available, I have edited the VM /etc/default/grub and now the contentes are:
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GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_CMDLINE_LINUX_DEFAULT="quiet console=tty0 console=ttyS0,115200"
GRUB_TERMINAL="console serial"
GRUB_SERIAL_COMMAND="serial --speed=115200"
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At the VM I have executed >update-grub

At the ProxMox GUI, Hardware->Display was changed from Default to "Serial terminal 0"

After rebooting the VM, the GUI Console->Xterm.js is now enabled...

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