See https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=1 for an example (with the vector 2022 skin). Looks like this is an issue with [[ https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=1&useskin=vector | legacy vector ]] as well.
== Steps to reproduce ==
Example (with Vector 2022 skin enabled):
* See Parsoid rendering of https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=1
* See non-Parsoid rendering of that page with https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=0
== Expected results ==
* The h1- headings would be rendered identically in both Parsoid and non-Parsoid renderings
== Actual results ==
* The h1-heading with Parsoid are much larger.
== Environments observed ==
* This is specific to Vector skin - also reproducible with legacy vector ([[ https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=1&useskin=vector | Parsoid with legacy vector ]]).
* This is not reproducible with the Timeless skin, for example ([[ https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=1&useskin=timeless | Parsoid ]], [[ https://en.wikipedia.org/wiki/Talk:WrestleMania_38?useparsoid=0&useskin=timeless | non-Parsoid ]]).
So, this bug seems specific to Vector skin and not Parsoid HTML or any transformations done in core.