The example from "nlwiki/ICE 3" is
<gallery> Bestand:ICE3_Schllenberg.ogg|thumbtime=14|ICE 3 door een tunnel </gallery>
Part of that is fixed by,
https://gerrit.wikimedia.org/r/c/mediawiki/services/parsoid/+/463125/19/lib/ext/Gallery/modes.js
But more work is needed, as mentioned in,
https://gerrit.wikimedia.org/r/c/mediawiki/services/parsoid/+/463125/19/lib/ext/Gallery/index.js