Confirmed
What Rebirth does
It is a reset layer for permanent multipliers.
TNT Incremental Rebirth Guide
The official Roblox page confirms Rebirth resets for permanent multipliers. This guide focuses on when to think about resetting, how upgrades and Runes affect planning, and what values stay held until tested.
Held values
What this guide does not fake
Exact Rebirth timing, costs, and multiplier values stay out of the guide until they are backed by testing or creator-owned notes.