When not logged in, the New Issue URL only redirects to an unhelpful
login page while the Issues page allows you to search for existing
issues and still offers a "New Issue" button.

AboutDialog is a newer libadwaita widget that is embedded within the window, and is adaptive depending on the window size to better suit different form factors.

"Controls in the header bars of primary windows should all have tooltips."
https://developer.gnome.org/hig/patterns/feedback/tooltips.html