Sure, it's in https://www.ato.gov.au/law/view/document?docid=AFS/EV-FBT/00...

"Plug-in hybrid electric vehicles - 1 April 2025 onwards From 1 April 2025, a plug-in hybrid electric vehicle will not be considered a zero or low emissions vehicle under FBT law."

However, I mis-remembered it - if you buy a PHEV by 1 April 2025 it will remain FBT-free.