A yellow cross means that mobs can spawn at night, a red cross means that mobs can spawn anytime.
A blue cross means that mobs can spawn if there is a spawner (1.18 only)

This mod provides users with a NEI-like light overlay.

This mod requires Rift, Forge or Fabric. (Fabric API, Cloth Config (Fabric) and Architectury are required for Fabric, Cloth Config (Forge) and Architectury are required for Forge)

Press F7 to toggle the light overlay, configurable through Controls Settings.

Config

• Rift 1.13.2: Config Screen Not Available
• Forge 1.13.x: Config Screen Not Available
• Forge 1.14+: Mod List > Config
• Fabric 1.14+: Mod Menu > Config