Moving to Parsoid 1.5.0 I ran the MCS diff tests. There I noticed that [[Media: ]] links behave very differently now.
[[media:Classical guitar scale.ogg|Sound]]
used to produce something like
<a href="./Media:Classical_guitar_scale.ogg" title="Media:Classical guitar scale.ogg">Sound</a>
Now it produces a link to a generic file type icon:
<a href="//en.wikipedia.org/w/resources/assets/file-type-icons/fileicon-ogg.png" title="fileicon-ogg.png">Sound</a>
You can observe this on my test page https://en.wikipedia.org/api/rest_v1/page/html/User%3ABSitzmann_(WMF)%2FMCS%2FTest%2FFrankenstein#Media.