Wikimedia Bugzilla is closed!

If you enter a text math formula, e.g. <math>y = x^2</math> as the caption for
an image (not a gallery image though), e.g. [[Image:whatever.png|<math>y =
x^2</math>]], some of the image's HTML attributes are shown as text on the page
because the caption includes a " as part of the image path when turned in to
HTML, and this HTML is used as the title attribute of the image.

e.g.
... alt="<img class='tex'
src="/wiki/images/math/1234567890abcdef1234567890abcdef.png alt="y = {x^2} +
{x^3} - 3" />" longdesc="/wiki/index.php/Image:Plotgraph2.png" />