Meaning of 記憶遺産

Hi guys
I was wondering what 記憶遺産 is?

It is part of a headline that says.

「特攻隊」の手紙などを「記憶遺産」に申し込む

Kamikaze letters etc 記憶遺産 in requested.

I know it's two words 記憶 and 遺産 memory and heritage.
Is this like a national heritage archive or similar?

よろしくお願いします

It's actually defined in the article:
ユネスコの「記憶遺産」は、世界の古い文書などを保存して多くの人に紹介しています。
and is probably a reference to the Memory of the World Programme run by UNESCO.

Because newspaper headlines are written to be extremely compact, you may find on occasion that the headline is unclear until after you've read the rest of it.

So it is only a reference to that program run by the UN to try and define "stored memories" into japanese. I thought it may have been a word like the English archive.