Facebook introduced a new, 3.03 version of its native iPhone application over the weekend, with the only changes being a few “bug fixes” and Chinese and Japanese language translations. That doesn’t sound like a huge update — it just means that you can now see Facebook in those languages when you select choose them in your iPhone settings.

But the fact that Facebook did these two translations is pretty interesting for a few reasons.

First, the iPhone app is the most popular native mobile Facebook app in the world, with 17.7 million monthly active users and 8.57 million daily actives as of today, according to our AppData analytics service.

And, up to this point, it has only been available in European languages, including English, Spanish, French, German and Italian, That’s not surprising, considering that most Facebook and iPhone users are in North America and Europe.

Meanwhile, Facebook has been growing fast across Asia, as we covered last week: The region, broadly defined to include the Middle East and the Indian subcontinent, grew by nearly 10 million people in October to reach 60 million monthly active users.

So why Chinese and Japanese? After all, Facebook is banned in mainland China, although 58,000 people apparently access it via proxy software last month. And the site has not found its legs in Japan, where it has only 795,000 monthly actives.

The Chinese translation is still a good fit with Facebook’s current demographics, though, because the site is huge in Hong Kong, Taiwan, and other Pacific Rim countries with a lot of Chinese speakers, including Indonesia, Malaysia, Singapore and the United States.

Why Japanese, and not other languages that have lots of Facebook users, like Portuguese, Malay, or Tagalog or Arabic? Facebook, for example, has quickly grown to 7.21 million monthly actives in the Philippines.

One reason may be that the iPhone has been doing increasingly well in Japan, and perhaps Facebook is hoping to capitalize on this success? Japan is one of the most developed countries in the world, and its mobile infrastructure is, too. And also, Facebook’ pseudo-rival, microblogging service Twitter, has been popular in the country for some time, and just got a new Japanese-language mobile site last month.

Anyway, this is all speculation. Also of note is that Facebook apparently has a new iPhone app developer, former Apple software engineer Owen Yamauchi — he recently replaced the app’s creator, Joe Hewitt. Last week, Hewitt announced he was quitting development on the app, out of disgust with Apple’s restrictive app development and approval environment. Yamauchi is now listed as the developer on the official Facebook for iPhone page, this appears to be his first update, and we’re interested to see what he comes out with next.