Tattoo Management Studio
From its first release in 2010 until 2017, REV23 Desktop was known as Tattoo Management Studio. Starting with version 17.1, released on March 1, 2017, Tattoo Management Studio was renamed and rebranded to REV23 Desktop. As a result, it is possible you will still see references to Tattoo Management Studio in old documentation, training materials, discussions, online communities, etc…
You can read more about this change in this blog post.