They're in a never destroyed singleton, not really a leak per-se but can confuse the gst leak tracer.
Pull request: https://github.com/WebKit/WebKit/pull/13974
Committed 264249@main (5a8358f7d8ad): <https://commits.webkit.org/264249@main> Reviewed commits have been landed. Closing PR #13974 and removing active labels.
<rdar://problem/109563277>