Anyone who uses the new website as an entry point to our other projects is being tracked by this service. The request to pixel.wp.com is made even when the Do Not Track header is sent. This domain is in the default block list for popular ad blockers.
I am adding fundraising-backlog because this issue is of extra importance to people who might click the "donate" link on the new site.
Edited to be less speculative
See also T201022: Third party resources loaded by wikimediafoundation.org