Hi @TWRobert !
Could you be more specific on your request? What do you mean by FEC? If you know how to do what you want using other vendor's equipment, give us an example, it could also help us as terminology may vary across different vendors.
Ok, so by 'FEC' you mean forward error correction... Yes, you can disable it by 'undo port fec enable' under a 25G port interface view.
The guide mentions only 25G ports, but it can be lagging behind actual software capabilities. You can test it, just enter the 100G interface context and type "undo port " (keep the space after the word 'port'!) and hit '?' on your keyboard. If 'fec' is among available options, then it is supported. If it's not there, then the guide is correct and it is only for 25G ports.