BCFtools Allelic Depth format nowhere explained?

Hi, I had a question about Allelic depth (AD) of BCFtools.

It has this format e.g. AD=262,18,0 – What number shows the depth of the REF and what is the ALT? and what is the ‘0’? I found 1 form where someone said 262 is the REF and 18 is the ALT. Is that correct?

I would also like to know why this format is explained nowhere in the manuals.. It seems to me like something everyone would be interested in.

Thank you in advance,

-Chris