Comment 7 for bug 1866259

I did some extensive digging and found why it is fixed in Adwaita and not Yaru.

Two weeks ago, the below commit was merged to gnome-shell. It checks to see if the string width is longer than the box width, and if it is, it switches to a hardcoded "leightweight" width of 13pt.

commit 80a869e7686adf772512069d7818bda0379190d8
Author: Jonas Dreßler <email address hidden>
Date: Mon Feb 17 19:59:31 2020 +0100
Subject: dialogs: Use a smaller font-size if the title width exceeds the space

Link: https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/80a869e7686adf772512069d7818bda0379190d8

This commit is present in the gnome-shell 3.35.91-1ubuntu2 package in focal.

Looking at the upstream Yaru sources, this "leightweight" tag is already merged, so I think this makes things Fix Committed.

https://github.com/ubuntu/yaru/blob/master/gnome-shell/src/gnome-shell-sass/widgets/_dialogs.scss#L32-L47

I built Yaru from source and tested it, and it works. For some reason the title is not Bold, no idea why, but the user experience is much better. Attached is a picture from upstream Yaru.

So Fix Committed. Will have to wait for Yaru master to land in Focal.