At this point I can now say that Mozilla intends to implement child-src.
[2] Define 'child-src's algorithms. (mikewest著, ) <https://github.com/w3c/webappsec-csp/commit/93e62e7bdd994500f64a3bc0702329bba4bd41ad>
[3] Deprecate 'child-src'. (mikewest著, ) <https://github.com/w3c/webappsec-csp/commit/2d91bd7e4b3d111afa9a41a67ff98e3cd673a2ee>
[4] Change the model for workers. (mikewest著, ) <https://github.com/w3c/webappsec-csp/commit/1af72ed19bf952402c514b7e7a966fb234d63217>
[5] Un-deprecated child-src (#313) (andypaicu著, ) <https://github.com/w3c/webappsec-csp/commit/af505e8a7458c467b418902b5860e3e1edebd1c4>
[6] Un-deprecated child-src by andypaicu · Pull Request #313 · w3c/webappsec-csp () <https://github.com/w3c/webappsec-csp/pull/313>