When I first heard it mentioned on the radio, and then I saw the name discussed in the newspaper, I tried to work out what it means, assuming it was kata ('word') + kijau (??). But then I could not work out what kijau might mean.

It was the missing 'h' that caught me out. But an absent 'h' at the start of a word is fairly common in Brunei Malay. For example, the following all have an initial 'h' in Standard Malay but none in Brunei Malay:
- (h)ari ('day')
- (h)itam ('black')
- (h)ujan ('rain')