Android phones…and I’m sure Apple…have a temperature sensor. I think.it is there to primarily monitor internal phone temps, but none-the-less it monitors temperature.
This could be a simple value add that quietly runs in the back ground even if the upper range of the thermo does not go much over 140F …especially if the notification is also coupled with a “rate of rise” (temperature)and best fit extrapolation.
Consider a scenario where a phone, left to monitor a room with typically a well controlled steady temperature sees a temperature rise from room temperature (72F) to 120F in 5 minutes. That’s a 9 degree/minute rise. That should not happen in a room with a history if stable temps.
Cell phones often shutdown above 140F. …which at 9 degrees/minute is only 2.2 minutes away, straight line rate of rise. If the rate of rise is exponential, it will reach shut off sooner and could indicate an even more serious condition exsists with the phone battery ,charging system, or within the room itself.
A notification set to trigger based on Temperature, rate of rise, and best fit curve (linear or exponetial) could be something that increases safety for people and property.