getNativeData() is being removed from MediaWiki core ( see https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1248131 )

The following extensions in deployed code still call getNativeData() and need to
migrate to getText() or serialize() before the core removal can land:

• mediawiki/extensions/ConfirmEdit (2 hits)
• mediawiki/extensions/WikiLambda (2 hits)
• mediawiki/extensions/Collection (1 hit)
• mediawiki/extensions/Flow (1 hit)
• mediawiki/extensions/NewUserMessage (1 hit)
• mediawiki/extensions/TemplateStyles (1 hit)
• mediawiki/extensions/Wikibase (1 hit)
• mediawiki/extensions/SpamBlacklist (1 hit — currently breaking Jenkins tests)

Reference: https://codesearch.wmcloud.org/deployed/?q=getNativeData&files=&excludeFiles=&repos=#mediawiki/extensions

Core removal patch: https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1248131