KDE, starting with Plasma 6.2, shows a notification once per year[1] and indeed it works[1]. They make donating[3] very easy.

[1]: https://pointieststick.com/2024/08/28/asking-for-donations-i... [2]: https://pointieststick.com/2024/12/02/i-think-the-donation-n... [3]: https://kde.org/donate/