I think it’s based on the xdg-desktop-portal accent color support, but there were specific hooks added to libadwaita to handle that desktop standard, at least that’s my guess based on this.
Definitely glad we have the major desktops all natively supporting accent colors now, it’s been a long time coming.
Yeah honestly if they could do a massive overhaul on performance and UX with the OSK then that’d solve the main complaint I’ve had with touch interfaces on Linux