This mod adds a custom Keybinding (F12) that when pressed makes a light overlay showing how the Block Light is at any given Block Position.
The Radius of the Overlay is around 7 Blocks, which can be changed by using the Page Up or Page down key when the Overlay is active.
Also the Overlay can be changed into "Spawning Mode" by sneaking and pressing the OverlayKey, which will change the Color coding of the Text to Red (for Spawnable light Level) and Green (For Save Light Level), just keep in mind it does not check if the Block itself is spawnable.
ModPacks can include this Mod. Feature suggestions are welcome.