Not sure why they added that back but the website states that no older cryptographic primitives - rsa, dsa, classic diffie-hellman, md5, sha1, 3des, arcfour,

Not sure why they added that back but the website states that no older cryptographic primitives - rsa, dsa, classic diffie-hellman, md5, sha1, 3des, arcfour, ... It is actually used in the code though. I didn't look into for what it was used though.