T165228: Query results are downloaded in wrong encoding comes back to haunt us again, this time just for the SVG download. Minimal reproducer query:
#defaultView:BubbleChart SELECT ("Ü" as ?üLabel) (1 AS ?size) {}
In the resulting SVG, the “Ü” is broken in a very peculiar way that I don’t even understand – it seems it’s UTF-8 encoded, but the encoded codepoints are U+00C3 “Ô U+0092 “PRIVATE USE TWO”, not U+00DC “Ü”.