According to Google Translate, this means “Japanese edition bonus track plan.”, which is (I guess) the two songs we know about.

According to iTunes Japan, there are 2 bonus tracks on the Japanese release (Drinking Soda (Bonus Track) & Western Silver Lion Cub (Bonus Track)).
But according to HMV Japan, the Japanese physical CD version only has 1 bonus track listed. It’s possible that only the MP3 album sold on iTunes contains 2 bonus tracks. In Japan, there are times when there’s a special track that’s only available on iTunes Japan, and not on the physical CD.
However, the info on HMV Japan isn’t for certain yet. When we get closer to the release date, it’s possible that the CD version bonus track will change to 2 tracks instead of just 1.
In any case, the 3 sites – Amazon Japan, HMV Japan, CDJapan – I listed all ship overseas. They all offer correspondence in English and foreigners can easily shop from there. I hope the fans outside of Japan who want to buy Mew’s Japanese album don’t buy them from eBay or Discogs, where they put a high premium on the CDs.

As soon as someone gets a legit, purchased copy in their hands, you can all have at it!

Sadly, No. http://www.cdjapan.co.jp/product/NEOIMP-10400