I noticed a sticky reddish stain that seemed to be coming from under an old (2005)laptop we just use for email and surfing.
Most of it was actually under the laptop or on the wood piece that elevates the back of it a bit. There doesn't seem any chance this was a spilled food or drink, there's not room behind it to set down anything.
My first thought was old battery, but I never heard of an Li-ON leaking. The material cleaned up off the table but not well off the wood, which almost looks burned. See photo. I have the back of the laptop propped up on a short piece of 1x2 because it started to overheat and shut down occasionally.
So I'm thinking low temperature pyrolysis maybe, releasing some of the pine oils. We had a fire at work that was caused by wood being heated over a period of years, not hot enough to burn but enough to change the wood and make it catch fire at a low temperature.