Force fixed frame interval sequencer option in 4.20-4.21

The option called force fixed frame rate interval used to render sequences that had very low fps smoothly at a give frame rate.
I have scenes where fps hits 2-3 fps but using the option in sequencer, it allowed me to render videos at my desired fps. With 4.20 I saw this in the change log.

But the option is missing completely from the sequencer or any other place.

Does any one know where it is and how to use it?

It’s been renamed and moved to the frame rate pulldown menu as “Lock to Display Rate at Runtime”

I think it is bugged or something.
There was not much difference with it enabled or disabled, there was frames skips with scenes having very low fps (1-2fps).
What fixed the issue for me was rendering it at 240 fps.