What does XX in "A Song for XX" mean?

[Linoa62]

From a translation by Delirium-ZerO on ayu-mi-x ( http://www.ayu-mi-x.com/modules.php?...iewtopic&t=669 )

Would you mind telling us the meaning of your album's title, "A Song for XX"

Ayu: The "A" in "A Song for XX" is both the "A" in Album, and the "A" in Ayu. As for the "XX", listeners can insert their favorite thing, the name of a person they care about, something like that. All that matters is that listeners imagine something there. Inside Ayu, there is only one meaning applied to the "XX". But, since everyone who listens will have different ideas as to who that song is about, I didn't want to limit the definition of "XX" by specifying its meaning to me, so listeners can themselves attach a meaning to it easily.