Deprecation: #78279 - Deprecate top.TYPO3.Backend.ContentContainer.iframe 

See forge#78279

Description 

The property top.TYPO3.Backend.ContentContainer.iframe has been marked as deprecated.

Impact 

Using this property will stop working in TYPO3 v9.

Affected Installations 

All installations using top.TYPO3.Backend.ContentContainer.iframe .

Migration 

Use accessor method top.TYPO3.Backend.ContentContainer.get() instead.