The game vault shows an open day of the 24th June.
It does not display a specific time, nor is that date localised to the users on timezone settings.
There's a countdown timer function shown on the main marketplace, showing the time left for "flash deals". Implementing a similar timer on the Vault site would help users better understand when specifically the game vault opens.
"https://anz.alienwarearena.com/marketplace/" < Add a countdown timer similar to the one here for the game vault opening.