In 309703c87b62cb97e20be19338467969cd8151c0, banners were made smaller. However there were a few visual regressions with the application page toolbar. The back button lost its left padding, and the application icon lost its bottom padding. See attached screenshot.
Created attachment 109467 [details] Applicatino Page toolbar items that lost their padding
Git commit d30f9ce9e444f199171ab6d7c301e3d6f161c5c7 by Aleix Pol. Committed on 28/12/2017 at 14:20. Pushed by apol into branch 'master'. Add margins on the application page header M +5 -2 discover/qml/ApplicationPage.qml https://commits.kde.org/discover/d30f9ce9e444f199171ab6d7c301e3d6f161c5c7
Close! That commit fixed the bottom margin issue for app icons, but not the lack of a left margin for the back button.
https://cgit.kde.org/discover.git/commit/?id=c8d5c23de57ca653d4442f8369b72251410e028b seems to have fixed that case, too.