These symbols are not true math symbols as supported by our Math extension, but use templates like https://en.wikipedia.org/wiki/Template:Intorient to generate SVG images for the symbols instead.
App content: https://en.wikipedia.org/api/rest_v1/page/mobile-html/Integral_symbol?theme=dark