Save uses an a href (link) with download attribute (https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#download https://developer.mozilla.org/en-US/doc

Save uses an a href (link) with download attribute (https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#download https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#...), which will usually trigger a normal file download. Share uses Navigator.share (https://developer.mozilla.org/en-US/docs/Web/API/Navigator/share https://developer.mozilla.org/en-US/docs/Web/API/Navigator/s...), which should invoke the browser’s “share” menu if it has one.