Android CONTENT TYPE - Is vnd.android.cursor.dir some standard constant defined by android?

Question

I have very basic understanding problem of Content types.

I went through lot of examples and text explaining the above term, but still have some basic understanding

Answer 1

Where did this come from?, or can I change it like vn.com.android.myexample.dir/

No, because "vnd" stands for vendor in MIME Registration trees, android in this case.