See {T93106} for background on WikidataPageBanner.
In 439656e01974e3cbc57902fb4ef33e71c1a386d5 (T293513) we moved TOC generation to ParserOutput::getText().
The WikidataPageBanner extension relies on being able to get the TOC HTML "by the back door" in the OutputPageParserOutput hook [code here](https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/extensions/WikidataPageBanner/+/8cb6f38ae0b633103b5c4db09e8069d01e11476b/includes/WikidataPageBanner.php#234), modifying it to remove the `class` and `id` attributes, inserting it into the output of its parser function [code here](https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/extensions/WikidataPageBanner/+/8cb6f38ae0b633103b5c4db09e8069d01e11476b/templates/banner.mustache#21) and then suppressing the "actual" TOC by setting `injectTOC` to false [code here](https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/extensions/WikidataPageBanner/+/8cb6f38ae0b633103b5c4db09e8069d01e11476b/includes/WikidataPageBanner.php#218).
Now that the TOC HTML is being generated in ParserOutput::getText(), there is nothing for WikidataPageBanner to insert.
# QA steps
Go to https://en.wikivoyage.beta.wmflabs.org/wiki/Bannerda and check there is a table of contents at the bottom of the banner
Check banner is on https://en.wikivoyage.beta.wmflabs.org/wiki/Salzburg