In gnome-terminal 3.20, we can choose either dark or light variant from terminal preference (irrespective of global variant). Hence no need for custom style. We keep the code for fallback and future reference.
Transmission has a visual bug where it doesn't change progressbar color quickly when changing state from active to bakdrop or backdrop to active. This makes entire thing appears buggy (#408)
Ideally I would like to change window frame backdrop color as well, but for now it works. It is probably going to break old metacity session, but we don't really support metacity.
During redesign terminal decoration was removed which left terminal with light background color. This restores terminal with dark background color & other minor tweaks. These tweaks needs to be modified again for GTK >=3.19.3, but for now it works.
GTK+ Places Sidebar in 3.18.x uses GtkLIst Box which is used by Nautilus and GtkFileChooserDialog. This fix adds padding in GtkPlacesSidebar widget. That way icon padding remains constant across all sidebar widgets.
Previously, background color of left, right and bottom part of windows are set transparent.This was making titlebar appears 1px wider than the window itself.This fix only affects those apps which are patched by ubuntu to use traditional titlebar over headerbar.