I think the issue is for an end user wanting to save a copy of a web page to disc.
But best you check the issue raised by the complainant. It isn’t my issue - my point in sharing it was to raise awareness about Web Components rather than get into a discussion about any particular issue in this topic. I created https://forum.safedev.org/t/web-components-good-or-evil/2729?u=happybeing for that.