An Implant Without a Source

Implant: Insomnia exists in the game's item data, but no shop, loot table, or reward currently hands it out — and the Pal Surgery Table never asks for it. It's an unused leftover: you can't get it, and you don't need it.

How to Get Insomnia Anyway

The passive this implant would unlock, Insomnia (nocturnal — the Pal works straight through the night), is one of the default options at every Pal Surgery Table — no implant needed, just 10,000 gold per surgery. That's a bargain for up to a third more output from a base worker; just budget for the sanity drain of a Pal that never sleeps — a follow-up Positive Thinker or Workaholic surgery covers it. See the implants guide for how surgery works and which implants are actually obtainable.