Ftdoverlays documentation

[Edoardo Tomelleri]

Hello,
I can not find u-boot documentation for the fdtoverlays option in
extlinux.conf files, here:
https://u-boot.readthedocs.io/en/latest/develop/distro.html?highlight=extlinux#enabling-the-distro-options
(is it supported? I've found that in January 2021 a related patch was accepted)
The docs refer to the boot loader spec
(https://systemd.io/BOOT_LOADER_SPECIFICATION/), where keys devicetree
and devicetree-overlay are supported.
Right now, I understand that u-boot supports keywords both 'fdt' and
'devicetree' with the same meaning, and 'fdtoverlays', but not
'devicetree-overlay', is this correct?
Thanks,
Edoardo