I need help identifying used MTB tire sealant I have a new-used MTB and I don't know what kind of sealant is in its tires. Does anyone know what this may be, or have a good resource for figuring it out?

The liquid sealant in the tire is a light brown, like coffee with milk. The dried sealant is a slightly darker brown.
The final result was "don't do that" (where "that" was to try to identify and match the existing sealant). Per advice in the comments I cleaned out the remaining liquid sealant (and the crud where the sealant had pooled and hardened during non-use), cleaned the inside with isopropyl alcohol and a lint-free towel, and then set the tires up with the sealant I have on hand (Stans). They have been holding pressure and riding great.