There is a big hole right behind the front wheel where mud and stone love to collect. There are report of riders in dry places having grass accumulating there and catching fire against the headers.
The prototype bikes and demo bikes in Morrocco were all equipped with a piece of metal to cover it.
Note that some replacement skid plates are going to cover this space, if you plan to add crash bars or third party skid plate check that you can still install those covers.
There is one on listed on the powerparts catalog (p/n 63503991044, €70, and note that the picture in the catalog is not exactly like the real thing) and third party jumped in to fill the gap.
One can make their own filler with a piece of mesh from any source, as this example.
There is another model, aluminium, branded by the company terratech, also available on ebay for $56 + $10 shipping for US/EU. Includes pop rivets as mounting kit.
And another one from coober, €59. Includes pop rivet as mounting kit.
And Bumot too, from Bulgaria (no price yet)
Another one from Braaap! on adv rider. Lasercut 2mm aluminium. Including mount hardware and postage, $50 for the mill finish, $65 for a satin black finish. Contact via DM on advrider for more details or ordering.
The most recent entry, if you like the Venetian blind look is this thing from twalcom, available in various colors including “racing orange” (note also the black bash plate of unknown origin).
By scouring ebay you can find more, like this one for example (€40)