Placeholder Text Converted from Confluence is Rendered as-is

Confluence pages can contain placeholder texts which are only displayed in edit mode, and invisible in read-mode.

A Confluence instance can have many documents with this condition - migrating it to XWiki will suddenly make all of these placeholder texts unconditionally visible on all pages, making the migration result hardly usable.

This might be related to CONFLUENCE-407 / GIT commit 06e3e75b91943dffe58e8b4a0b7c637f42831048, though I'm not fully sure.

It would be good to remove these placeholder texts, or only render them into converted templates, not regular pages.