Breaking: #72870 - Removed RTE transformation ts_preserve and preserveTags 

See forge#72870

Description 

The RTE configuration TSconfig option RTE.default.proc.preserveTags to preserve special tags has been removed.

The RTE transformation mode "ts_preserve" to change special preserved tags and migrate to <span> tags has been removed.

The according methods TS_preserve_db and TS_preserve_rte within RteHtmlParser have been removed.

Impact 

Setting the TSconfig option or the RTE transformation mode has no effect anymore.

Calling the removed PHP methods directly will result in fatal PHP errors.

Affected Installations 

TYPO3 instances with custom RTE transformations using the removed "ts" transformation mode, or a custom transformation mode.

Migration 

Use the RTE processing option RTE.default.proc.allowTags to include the tags without rewriting them to custom <span> tags.

If special handling is still necessary, an existing hook can be used to re-implement the logic.