This page highlights a few projects where redlining was important for handoff.
T-Mobile T-Shirt Redline Example
Redlines for T-Mobile used a T-Shirt style. I had to redline various desktop and mobile flows. It was pretty straight forward and the production work allowed me to have a good sense leading into building their symbols library.
Redlines did not need to be created for our devs at Samsung as we used Zeplin for handoff. This allowed us to work more swiftly and alter any discrepancies within differing designs. There were a few times after developers went live that the UX designers (myself included) would sit down and do a audit to make changes to designs that were not directly translated.