Finding bucket Fill Threshold slider

[jimav]

Hi, Inexperienced Gimp user here.    Where exactly is the Bucket "Fill Threshold" slider?  I see it in the Bucket Fill tool options in some Youtube videos but don't see it in the similar options screen in my system. 

A screenshot of what I see is attached as "gimp_no_FT.png"

A screen capture of a youtube video showing it is "youbube.png" (sorry, fuzzy).

What am I missing/confused about?

Thanks for any help.
-Jim

Gimp 2.10.36 on Ubuntu 24.04