There is a amusing little set of easter eggs that can be found in Deus Ex: Mankind Divided. At any point while you are in the Czech capital of Prague, head on over to The Music Box in the northern section.
The Music Box itself doesn’t really offer much, there is a computer containing three mails, behind level one security. In basement, you can put a Biocell in a socket on the wall (corner) to unlock a secret safe, and the building itself is connected with the nearby flat at M3,32 via vents filled with poisonous gas (which when explored will give you +200XP), as well as leading to side passage in/out at M3,34 (which gives +200XP).
Once inside you will notice that the music store is filled to the brim with vinyls, and those who decide to take a closer look will recognise many of these vinyls by their parodic cover art.
The American actor Ron Perlman is famous among video gamers for his voice work most commonly as the Narrator for the Fallout Series, since the start with Fallout in 1997 to the most recent instalment of Fallout 4 in 2015.