hi, yes, the transparent colour is always there.
now i realized one thing: when i open my 4 colour gifs i get this kind of palette:
transparent mask (not used), 4 colours i actually used, 3 more black colours i didn’t use.
i don’t know if this is caused by the way aseprite imports gifs or if it actually exports them like that.
i can remove those three black colours, but i can’t remove the transparent colour in indexed mode, because aseprite will expect one of the colours in the palette to serve as transparent.
all in all, the best way would be - as BraidAcer recommended - to store your work in aseprite / ase format and use gif files only for export. aseprite format will always have a palette consisting only of colours you set up. exported gif will keep that palette as long as you don’t use other colours in the image (those are going to be added to colour table during export). accidentally using colours outside the palette can be prevented by working in index mode (you will need one transparent colour for that anyway).
also, you can check number of colours in your gif or png files with pj image inspector after export. if that online tool says there are 4 colours, then there are only 4 colours in your image and you don’t have to bother yourself thinking about what is stored in colour table unless you have specific reason for that.