Minecraft wiki entry for BE, associated text: Block entity data
Tags common to all block entities[show]
 GlowingText: 1 or 0 (true/false) - true if the sign has been dyed with a glow ink sac.
 Color: The color that has been used to dye the sign. The default value is "black". One of "white", "orange", "magenta", "light_blue", "yellow", "lime", "pink", "gray", "light_gray", "cyan", "purple", "blue", "brown", "green", "red", or "black".
 Text1: First row of text.
 Text2: Second row of text.
 Text3: Third row of text.
 Text4: Fourth row of text.