For reasons known only to VAG they call an AGM battery 'fleece'.
With absolutely no offense intended - VAG usage of the term "Fleece" ain't really so surprising - IMO, of course!
"AGM" refers to the Battery type and "Fleece" refers to the distinguishing feature of this battery type in its manufacturing process. "Fleece" refers to the weave of the glass mat in an AGM battery - from HERE
I'm most certainly NOT an apologist for VAG - but, as a marketing/sales descriptor that is used by battery sellers for the general buying public, "AGM" is likely more appropriate (i.e. it's probably a more recognizable word to the great-unwashed masses).
But as a descriptor for an adaptation channel setting inside a control module which VAG has designed to be accessible only to their engineers and to their trained master-techs, is it so surprising that VAG has used a "technical" term? Maybe not (again IMO, of course)?
PS: And yes, the normally brilliant Humble-Mechanic has gotten it wrong in this instance (he should revise his video). Binary AGM batteries are special high performance batteries that are seldom (if ever) used in cars. If you consider AGM batteries to be expensive, you will very likely not be able to afford a Binary AGM battery - if you can find one (they are impossible to source)!!
PPS: The "great-man" (not really -he's a God with feet of clay IMHO) at Ross-Tech recommends "Fleece" as the correct setting for AGM - read Uwe's response in post #5 of the thread HERE
(note date 2020)