I'm pretty sure the reason why the file was flagged as suspicious is probably because it's a java script file. Should be safe. It's usually the same for mods for minecraft.
9:07 it would be illegal to implement optifine into a Minecraft client without a license, so it is a good thing that the client does not have optifine otherwise the seller would be breaking the law.
ign : MrAaqua why: my parents cant afford the cape and my friends make fun of me for not having any cosmetics and call me poor and the cape looks fire and happy new year