Firesight

Firesight is a Minecraft Fabric mod that provides visualization to help players understand fire spread mechanics in Minecraft. It uses Litematica and MaLiLib and offers real-time block highlighting to show where fire can spread.

An air block will be highlighed if fire can spread to it. This works in a radius around the player that can be configured. Setting it to a high number does impact frames. The visualisation can be turned off using a hotkey (default F8), and a settings menu can be opened using a hotkey (default M + F8).

It's my first mod. I am not responsible for killing your frames, although if you have so many places for the fire to spread that you get lag, you probably have bigger issues.