That's your
Mods\%INIT% subfolder. It's supposed to contain content files (in *.swf or *.mod format) which will be loaded automatically when the game starts up.
If you installed the mod correctly (or if you're using
sby's Loader Pack) then the settings file should be in your Settings subfolder:
%SDT_Main_Folder%\Settings\animtoolsV15settings.txt
I've been looking through my files
That's a waste of your time. You already
know the filename that you want; you should employ the search feature provided by your operating system. I sometimes make disparaging comments about Macs
(because of stupid anti-skub tribalism) but they're quite capable of handling a use-case like this one.
I can't find animtoolsV15settings.txt.
If you're accidentally deleted the file then you can grab a new copy of the
animtools ZIP archive and extract the settings TXT file.