The holo-letters were a type of holomessages recorded inside the datacards that individuals used to communicate.
The holo-letters first appeared in the new Star Wars canon in the audiobook Dooku: Jedi Lost, written by Cavan Scott and published on April 30, 2019. Its spelling was confirmed by the script release of the audiobook on October 1, 2019. In the Star Wars Legends continuity, the hololetters first appeared in the 1997 novel Young Jedi Knights: Delusions of Grandeur, written by Kevin J. Anderson and Rebecca Moesta.
The holo-letters first appeared in the new Star Wars canon in the audiobook Dooku: Jedi Lost, written by Cavan Scott and published on April 30, 2019. Its spelling was confirmed by the script release of the audiobook on October 1, 2019. In the Star Wars Legends continuity, the hololetters first appeared in the 1997 novel Young Jedi Knights: Delusions of Grandeur, written by Kevin J. Anderson and Rebecca Moesta.