(SMIL / begin/end) <begin-value-list>/<syncbase-value>

[strarsis]

The syncbase value can references to an ID, syncbase being one of the allowed values of a <begin-value-list> (also applies to end attribute).

What kind of primitive is this? Is this <ID>.<Component> syntax unique to syncbase value?

Also, is there a style-equivalent to this?

[skyclouds2001]

this is a not-related PR which should be removed