Use case

Gnome* 48 (from March 2025) switched its default font from Cantarell to Adwaita Sans: https://blogs.gnome.org/monster/introducing-adwaita-fonts/.

Flutter likewise should switch to use Adwaita Sans if available in its font fallbacks.

Adwaita Sans is a slightly tweaked version of Inter, and therefore fits in with Roboto and the other Linux fonts listed in _helsinkiFontFallbacks.

*For context, Gnome is one of the two most popular desktop environments on Linux, and is used on Ubuntu.

Proposal

   static const List<String> _helsinkiFontFallbacks = <String>[
     'Ubuntu',
+    'Adwaita Sans',
     'Cantarell',
     'DejaVu Sans',
     'Liberation Sans',
     'Arial',
   ];

Adwaita Sans should be preferred over Cantarell, but the Ubuntu font should be preferred over either.