Xenospit (From what I can tell) is not related to anything, it is Juiced alien parts, and not from any particular alien, see those Greys? Juice 'em and you get Xenospit, Elcor? Juice them, you get Xenospit.
When Piecewise says we can make xeno-spit locally I think that Piecewise the Basalisk could also count, actually.
Piecewise also went on to say that we can make it using the CSF's on a certain inmates ride.
Now im not exactly sure what CSF stands for, but the only inmate with anything resembling an alien vehicle is miyamoto with his bigass synthflesh avatar. So basically im assuming xenospit is some kind of neurofluid used in the control interface that requires a certain minimum flesh volume before it is produced any meaningful amount.
Oh yhea, CSF could stand for Concentrated Spinal Fluid, but he didn't say that you could only make it with a synthflesh construction, not to mention what it says on the
Official Einsteinian Roulette Wiki, it states that 'Contains Random Xeno part (Effects vary)'.
Taking one instance of something that has been stated it's made from any alien part does not mean that it is solely related to that specific thing, of course, taking CSF from a synthflesh avatar and putting it into a bottle means that it's called Xeno-Spit, not because that is a specific ingredient that makes up the Xeno-Spit, only that Xeno-Spit is a catch all term for anything (Liquid? If not, then technically you could also call Blue Smokes Xeno-Spit.) bottled up coming from an non-Earth Native creature.
Course, if you want to get into specifics, we don't know what the cut off point is for a non-earth native creature to a earth native creature, I mean, we don't know if Xan could be called a non-earth native creature, his species originally came from earth, but now you really can't call him human, can you?