They will remove non-positive feedback left complaining about customs fees charged to buyers, or customs delays.
However, in order to be eligible for feedback removal, sellers must point out in their listings that cross-border transactions may incur import duties and that these are not included in the shipping fees; they’re also advised by eBay to clarify that they will not mark items as “gifts” to avoid duties. Notices about import duties must be “prominently” included in the listing and be in a font size no smaller than the rest of the item description.
Sellers who trade within the EU might like to also add that trading within the EU should not normally incur customs fees; in my experience, UK and European buyers are not necessarily aware of this, and need some reassurance.
The announcement has been made on eBay.com and there has been no corresponding announcement for any other eBay site, so it’s not immediately clear whether the new policy will apply to non-US sellers or not.