If it only applied to games sold for profit (or with microtransactions) it would be okay, but basing it on installs leads to things like that a Unity developer

If it only applied to games sold for profit (or with microtransactions) it would be okay, but basing it on installs leads to things like that a Unity developer should avoid including their game in a charity bundle unless they mostly want to donate to Unity. E.g. Fanatical's Stand With Ukraine Charity Bundle would have cost each developer ~$2000 if they were on a Personal/Plus plan. It's not a huge amount, but Unity does not deserve it.