TYPO3 Core

well it works on the "old" plugin

you could target it as feature...
BUT, like I wrote, the code in the "new" controller (for highlighting) is already there - but doesn't work

You can enable the highlighting etc with the typoscript option: plugin.tx_indexedsearch.defaultOptions.extResume = 1

and change your fluid template: {description} should be {description -> f:format.raw()}

But it would be great if you could test the patch

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/49697

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/49697

Patch set 4 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/49697

Patch set 5 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/49697

Patch set 1 for branch TYPO3_7-6 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/49809