Before https://gerrit.wikimedia.org/r/#/c/90449 :

<meta property="mw:PageProp/categorydefaultsort" content="Page, Main" data-parsoid='{"src":"{{DEFAULTSORT:Page, Main}}","dsr":[1800,1826,null,null]}'/>

After:

<meta property="mw:PageProp/categorydefaultsort" data-parsoid='{"src":"{{DEFAULTSORT:Page, Main}}","a":{"content":null},"sa":{"content":"Page, Main"},"dsr":[1800,1826,null,null]}'/>

This breaks editing of defaultsort in VisualEditor for obvious reasons, but it also triggers a failure mode in VisualEditor where missing content attributes aren't expected and are normalized to content="null", triggering corruption warnings and changing {{DEFAULTSORT:Foo}} to {{DEFAULTSORT:null}}. I'll fix that in VE.

Version: unspecified
Severity: normal