Grade A male bovine excrement.

There might be a tiny amount of lubrication on the bearings but not enough to leak out. There's more likely a bit in the cooling fans but again it's still a tiny quantity. In 20+ years of dealing with PCs I have yet to encounter a liquid inside that is not due to something being spilled on the machine.

Since you say it's a new laptop I would be more inclined to think along the lines of traces of chemicals used in production. There will be traces of flux on the board from when it was soldered, there's a wide range of chemicals that get used as thermal paste between hot components (especially the CPU) and their heat sinks and those most certainly remain in the machine. As it goes on as a paste there's a solvent of some sort that will slowly be driven off. While much of it leaves upon first use older material does still get harder with time which means it's still leaving.