Where are the mouse themes read?

[ToddAndMargo]

Hi All,

Fedora 41
Xfce 4.18

I have been reading through
  https://gitlab.xfce.org/xfce/xfce4-settings/-/tree/master/dialogs/mouse-settings

to try and figure out where mouse settings is reading the
installed themes shown in the red block here:

    https://ibb.co/SDbj64kD

I think is might start with line 542,
     if (xfce_rc_has_group (rc, "Icon Theme"))

but I am thoroughly confused.

Are the installed mouse themes not stored in a file
somewhere or an X11 call that will list them?

Yours in confusion,
-T