Bukkit Application for Android Mobile Devices

Yes, but there is only an online documentation available.
There's no actual file to download and then edit. The API that they put out to the public is only used for reference.

Correct about the directory name. Here's an example when I go on my XenForo forums, with the add-on installed (sorry if this accounts for advertising, only using it as an example) http://ggforums.tk/mobiquo/mobiquo.php

When I went to Bukkit's directory:

http://bukkit.org/mobiquo/mobiquo.php

It appears it's outdated?

 

Correct.

As for the API, the documentation seems definitely detailed enough to write a client for it, but if additional information is required you would only need to sniff what the official app is doing (or indeed decompile it) to gather any additional information you'd require.

 

What do you mean "there's no actual file to download"? It's a rest interface, there's nothing to download.

 

He wanted to download the tapatalk source, so he could edit it, probably.