Economy, but non-changeable fare

I just noticed this when looking for flights to Asia routing through Tokyo. I have never noticed this before and assumed maybe they changed Basic Economy (BE). Looking at the details of the cabin experiences though, it appears that it is not BE, but a whole other fare class that is Economy but without the ability to change the ticket. Posting this just to make folks aware of this so you do not mistakenly make a mistake booking this fare if you think you might need to make changes to your itinerary later.