In the end, the string is not nonsense — it is poetry. It captures how we name our fragile creations: a mash of identity (cat-boy), time (that summer), technology (portable), and incompleteness (01). We may never play it, but we can still feel the humid afternoon it was made, a single developer in a Tokyo apartment, hoping someone, somewhere, would understand.
Regarding the "paper" aspect of your query, this likely refers to one of the following: nekopoishounengaotonaninattanatsu01 portable
If you cannot locate the exact game, these provide identical experiences: In the end, the string is not nonsense — it is poetry