Minecraft wiki entry for Block_entity_format, associated text: : The block entity's root tag.
 TextOwner: Unknown.
 IgnoreLighting: True if the sign has been dyed with a Glow Ink Sac.
 SignTextColor: 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".[needs testing]
 TextIgnoreLegacyBugResolved: Unknown.
 Text: The text on it.