What are the yellow dots on tyres?

I was browsing websites looking for info regarding those red and yellow dots on the tyre sidewalls and could have sworn I’d seen an MCN feature about them being factory balance markings and where they should be in relation to the valve position but can’t find it anywhere. Can you offer any info?
‘Chap’, Mansfield
 
We’ve started calling those dots “VIMs”, for Valve Identification Markings and they should be positioned next to the valve, not opposite it. That way, the tyre will need less balancing up with weights.