Found it.
https://forum.audacityteam.org/t/de-ess-plug-in-for-audacity/51993/13
The DeEsser defaults are not the best and that’s the set I use.
One shortcoming of the DeEsser is the need to produce the voice track first, before you apply the tool. That’s what the audiobook mastering suite is doing. That’s not a bad way to stabilize your track volume for your products, although it does less well with music. Do the voice corrections first, then add music.
Koz