From T328695#9827776:
BREAKING CHANGES FOR LATER (timeline: likely after Parsoid readviews rollout):
- Drop the reference-text class from Parsoid and legacy.
- For the un-named ref backlink case, we could move the rel tag from a[rel=mw:referencedBy] to a span.mw-cite-backlink wrapper.
Additionally:
- Drop any b/c duplicate class from <references /> output