New to Eclipse Photon, see https://www.eclipse.org/eclipse/news/4.8/platform_isv.php#Platform

Code mining and inline annotations allow an editor to display test (or graphics) inline with editor text. This may be useful for parameter name labels or category method sources or for other purposes. It may even be good to allow DSLD to specify text to be displayed inline with contribution.