TYPO3 Core

... and make use of PageRenderer->removeLineBreaksFromTemplate i production mode.

That won't work if pre-tags are in use or intended line breaks (for example in javascript):

var myText = 'this is my message
with 2 lines';

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/28999