In recent hotfixes, a possible buff for the Delves Bonus Weekly Event was revealed granting players bonus Companion experience, Delver's Journey experience, and Undercoin gains!
Delves OverviewDelve Rewards Sign of the Explorer Buff The Delves Bonus Event begins on October 1st. In the event calendar, the event states that Delves will grant «increased rewards for intrepid explorers».
Blizzard has not confirmed this as the buff for the event, but we recently found a Sign of the Explorer buff in hotfixes.
This buff has the «Sign of» prefix that is resemblant of other weekly event buffs. With bonus rewards, this event is a great time to be working on leveling Brann Bronzebeard along with leveling the Delver's Journey.
Delver's Journey progress rewards Delver's Dirigible Schematic: Lantern WingDelver's Dirigible Schematic: ExhaustDelver's Dirigible Schematic: Front-Mounted LanternDelver's Dirigible Schematic: ZeppelinDelver's Dirigible Schematic: Brown PaintTrusty Hat: Use: Throw the hat to an ally!You can now purchase Restored Coffer Keys for 0 UndercoinHidden Stash from Deep Within: this is 0 Resonance CrystalsWarbound Equipment Set: you can now purchase Adventurer 4/8 (iLevel 580) Warbound equipment