Contrast this with the slash or dash notation, where both mm/dd/yyyy and dd/mm/yyyy are prevalent in the world. But 2020-08-06 is unambiguous in the same way that 06.08.2020 is: the only convention in common use is yyyy-mm-dd.
Contrast this with the slash or dash notation, where both mm/dd/yyyy and dd/mm/yyyy are prevalent in the world. But 2020-08-06 is unambiguous in the same way that 06.08.2020 is: the only convention in common use is yyyy-mm-dd.
While slash is the most common, use of hyphens and dots as separators for US-style dates is not at all unheard of in the wild for manually formatted dates. The fact that it doesn't show up in lists of national “preferred formats” and doesn't tend to be commonly implemented as a prebaked format in software doesn't mean it's not a real thing people see and will interpret dates they see in light of.
So, yeah, there is a convention to write dates exactly that way.