Are synthetic leaders immortal?

I'm 99% certain they'll act just like a normal species, that is, they'll die. If you look at the mod files you'll see that AI is created just like every other species. The only thing that could impact any species lifespan is traits. After doing some digging around I found that the trait for being a synth is trait_robotic_3. I looked through the species traits files (in the trait folder) and found this:

trait_robotic_3 = {
    cost = 0

    initial = no
    modification = no

    modifier = {
        tile_resource_engineering_research_mult = 0.20
        tile_resource_physics_research_mult = 0.20
        tile_resource_society_research_mult = 0.20
        tile_resource_energy_mult = 0.20
        tile_resource_minerals_mult = 0.20
    }
}

As you can see there is nothing in here about being immortal, or even long lived. But wait, you may say, this is only the species traits file, what about ruler traits? Well, I checked those as well and there was nothing in there about immortality for anybody, including synths. Additionally, we can see that the devs can modify ruler lifespan in the species traits because this is demonstrated by the venerable trait, among others.

This makes sense from an in-game perspective as well because synths are designed to live (and die) in a very similar manner to their creator species.

Edit: regarding the Playable Robts mod.

In the current git repo there's a suspicious looking line:

playablerobots_immortal_modifier = {
  leader_age = 10000
}

so the leaders don't become techically immortal just very, very old.