In Minecraft 1.14, the following feature was added:
"Right clicking on signs with dyes will now change the text color."

As such, signs now have the following block data:

• 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.

Currently, you can get Text1, Text2, Text3, and Text4 through the Sign interface (i.e. https://hub.spigotmc.org/javadocs/spigot/org/bukkit/block/Sign.html)

However, there's no option to get the sign color.

Ideally, there should be getColor and setColor methods on the Sign interface.

Thanks!