Why an iCloud email looks like this

I recently got an iPhone after having Google for 6 years. After loading all my accounts on my new iPhone, I was deleting drafts out of one of my emails and noticed an iCloud email address I had started and never finished an email to had a strange look to it. It was another iCloud email address but it was partially obscured and looked like this Jr******@icloud.com…… why did this look the way it did??