The Devron sector contains areas of space that feature in a number of pivotal Star Trek episodes/movies.
Continuing from the Sierra Sector, we have the Romulan Neutral Zone, with a dotted line showing the change to the zone after the Treaty of Algeron. At about the point the treaty change ends in mid-map is the Bassen Rift, where the Enterprise-E fought the Scimitar in ST:Nemesis.
Just across the NZ from the Bassen Rift is the section of Federation outposts (specifically Earth Outposts 2,3, and 4) that were attacked by a Romulan warbird, the first known Romulan contact with the Federation since the end of the Romulan War (as related in the TOS episode “Balance of Terror.”) It is supposed that during that time frame this section of Federation space was not known as the Devron Sector, but instead was considered an extension of Sector Z-6.
On the border with the Sierra Sector are the systems known as Rachelis (where Science Station Tango Sierra is located) and the Aucdet system, both mentioned in the TNG episode “The Child” and Moore’s Star shown in an Okudagraphic in the TNG episode “The Defector.”
Near Eden is the Hobus system, where the supernova which destroyed Romulas originated; here it is shown in its original state as Alpha Corvi (Alkiba in ancient astronomy.) However, after the supernova it is referred to as the Hobus Cinder as Alpha Corvi was completely destroyed.
Deneb and Dessica are shown in the same x,y position (29,21) but are separated by about a light year with Deneb being just below Dessica.
Deneb is known in astronomy as Denebola (Beta Leonis, Deneb Alased), but long before TOS (likely even before ENT) it was referred to by its truncated name to avoid confusion with Denobula, a system in the Alpha Quadrant. Of course this name truncation would cause endless confusion with every other Deneb variant, but this is the most logical Deneb given its proximate location to the central core and overwhelming presence to others in the Beta Quadrant (Denebian Slime Devil can’t just be a casual insult a Klingon would pick up on by the time of TOS.) Deneb is mentioned as visited or visited in the TOS episode “I, Mudd” and the TAS episode “The Pirates of Orion.”