qr/^UCS2-le$/i => '"UCS-2"' -- what is it?

Hello, Dan!

A two-pence question (very quick and probably foolish :-)

What is the marked alias about?

    define_alias( qr/^UCS-2LE$/i    => '"UTF-16LE"',
                  qr/^UCS2-le$/i    => '"UCS-2"', );
                  ^^^^^^^^^^^^^^^^
                  
    define_alias( qr/^UTF-16BE$/i    => '"UCS-2"',

All I could understand meant that UCS-2 is BigEndian.
Why is UCS2-le aliased to it then?

- Anton