There are a couple of mentions of a starship called USS Yelchin. This is a memorial reference to actor Anton Yelchin who played Chekov in the Star Trek Kelvin movies. Yelchin died tragically in a vehicle related accident in 2016.
This episode takes its title from the two episodes of Star Trek: The Next Generation (1987), when Spock and Picard began facilitating the unification of Vulcans and Romulans (Unification I (1991) and Unification II (1991)).
The first mention of the Romulan/Vulcan connection on Discovery
The Romulan doctrine of absolute candor was introduced to the Trek universe by Absolute Candor (2020) less than a year earlier.
The third part of a three-part episode. Originally only a two-parter, Star Trek: Discovery (2017) this episode was added as a third part/continuation in 2020.