In the Star Trek: Deep Space Nine Companion (pp. 34-35), writer Robert Hewitt Wolfe confirmed that this reference was a way to tip the hat to the Katra transfer discussed in Star Trek III: The Search for Spock.A similar transfer process was used by Tieran, an Ilari dictator, in the Star Trek: Voyager episode "Warlord".
Sometime in the 2230s, after a bombing at the Vulcan Learning Center resulted in young Michael Burnham's death, Sarek used his katra to bring her back to life. As a result, Burnham retained part of his katra even years later, and with it, a remote connection Sarek described as "more than a mind meld". In 2256, after Sarek was targeted by Vulcan extremists, Stamets boosted this connection to allow Burnham to revive Sarek so he could send their rescue shuttle a signal. (DIS: "Battle at the Binary Stars", "Lethe")