child-src is not deprecated as of yet, and still has full browser support: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/child-src
I do see some articles showing it was, however, it has since been un-deprecated as of December 2018
Interestingly enough though, W3C has marked frame-src as deprecated… as of July 31st: https://www.w3.org/TR/CSP3/#changes-from-level-2
However, it is still supported in all the major browsers, and is yet listed as such here: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-src so… it will likely not go anywhere anytime soon…
Agreed, I can certainly add that to wordpress defaults. Next version 🙂
Just wanted to give you a heads up @knutsp I will likely be pushing this update over the next couple of days… I had too many items in that default, so I have had to remove some from it (items like wpengine, fontawesome, etc… are all now non-default), but I have verified against the base Twenty Twenty theme-set (2020 – 2023) all is working fine for it even in customizer and the new full theme editor.
