[1] Use USVString for all URLs ( (domenic著, 2016-05-20 22:02:29 +09:00)) https://github.com/whatwg/html/commit/018b983b77b2cd908f6d00100e7e0abe893dd2c3

[2] Restrict (un)registerProtocolHandler to secure contexts (ericlaw1979, 2019-11-20 03:44:22 +09:00, 2021-03-17T09:35:47.000Z) https://github.com/whatwg/html/commit/6772a0342e6ffebc922c60c770dce87371b6c968

[3] registerProtocolHandler and unregisterProtocolHandler should require SecureContext · Issue #5068 · whatwg/html (2021-03-17T09:40:44.000Z) https://github.com/whatwg/html/issues/5068

[4] Add SecureContext limitation for [un]registerProtocolHandler API by ericlaw1979 · Pull Request #5080 · whatwg/html (2021-03-17T09:43:07.000Z) https://github.com/whatwg/html/pull/5080