Another genuine question: is there a good reason to use a closed source UI framework in 2022? Given the number of high quality, cross platform UI frameworks av

Another genuine question: is there a good reason to use a closed source UI framework in 2022? Given the number of high quality, cross platform UI frameworks available today this should be a consideration. Inevitably, while developing a UI, I find it necessary to investigate some part of the framework implementation. This is impossible with a closed source framework. Indeed, many of the complaints that appear on this site seem like exactly the sort of mysterious behavior one faces and might be resolved with access to the source. SwiftUI is closed source, correct? I made an effort to discover the source and it doesn't appear to be available.