For example, a string with an effect: Solid Pattern
static const char _data_FX_MODE_STATIC_PATTERN PROGMEM = "Solid Pattern@Fg size,Bg size;Fg,!;!;;pal=0";
What do abbreviations Fg, Bg, Fx means?
Fx, or fixed is it just a color?
Bg, or background is it a background color?
Fg - there is not even an assumption.
This is usually one of the colors used by the effect, but not the effect itself.
it seems to be true
else if (i==0) btn.innerHTML = "Fx";
else if (i==1) btn.innerHTML = "Bg";
else btn.innerHTML = "Cs";
Whats mean Cs, custom?