Created attachment 6723 Bolded Summary Text Patch Found another issue with the GTK3 migration. The summary text is no longer bolded. Attached is a patch.
Created attachment 6724 Bolded Summary Text Patch V2 Updated version of patch placing markup variable assignment after g_return_if_fail to prevent possible memory leaks.
I generally like this as a default setting but in fact themes had to handle the bold font in Gtk2 (the markup for bold summary was not there by default). I'll consider adding this though, even if it means a slight change of behavior.
That explains why I couldn't find it in the older code. Perhaps its best to leave it as it is and let the theme handle it as it does now.
Alright, let's keep things as they are then!