"seven layers deep"
same explanation as room 7, it's just two things. i'll explain them both.
the first of the two is the release date of the .gif file format.
Initial release: 15 June 1987
"afterlife.gif"
okay, now we have the first part, now to explain the second thing which is "made in an abyss", which hints towards the manga series "made in abyss".
as for the flavortext, there is only one thing in the manga that correlates towards being 7 layers deep... the abyss itself, which is seen in the gif.
so, we follow the letter positions the image gives us, ignoring spaces, which gives us this:
Edge of the Abyss
Forest of Temptation
Great Fault
The Goblets of Giants
Sea of Corpses
The Capital of the Unreturned
The Final Maelstrom
...which gives us our next answer: separations.