Minecraft wiki entry for End_Gateway_(block), associated text: An End gateway block emitting a magenta beam after being created.
An End gateway block emitting a purple beam after teleporting an entity.
Comparison between the magenta (left) and purple (right) beams.
An End gateway block emitting a yellow beam after teleporting an entity (before Java Edition 1.11).
An interior view of an End gateway block.
Comparison of the historically emitted yellow beam with a yellow-tinted beacon beam.