Kedayan

The Wikipedia page on Kedayan (here) claims it is "the de facto national language of Brunei", which is rather startling, as most people in Brunei consider themselves to be speakers of Brunei Malay.

In addition, the Wikipedia page claims that there are 530,000 people living in Brunei, which seems a bit excessive. A more reliable estimate of the population (here) is about 433,000 at the end of May 2018.

I guess Wikipedia is not always accurate!