Thanks for the report, filed an investigation here: https://bugs.webkit.org/show_bug.cgi?id=253063 You may have success with following instructions, replacing Safari with SafariForWebKitDevelopment: https://apple.stackexchange.com/questions/429814/how-do-you-programmatically-enable-the-develop-menu-in-safari-15-on-macos-12 Unfortunately at the moment I do not immediately have an environment to reproduce the problem here.

Thank you for the report. If you belive it is a Safari issue, best approach would be to file a feedback report, see https://developer.apple.com/bug-reporting/. A runnable example that demonstrates the issue would be the most helpful.

The polygon shredder redux, Cheron particles likely are rendering to 32-bit floats or filtering float textures. Rendering to 32-bit float texture is currently not supported on any iOS device. Texture filtering of 32-bit float textures is currently not supported on any iOS device. On 15.3, EXT_float_blend and EXT_color_buffer_float were incorrectly advertised. This bug was fixed in 15.4. The application should use https://www.khronos.org/registry/webgl/extensions/EXT_color_buffer_half_float/ for both, and work with half-floats on if the 32-bit float extensions are not available. For hevc video missing transparency, please file a feedback request against Safari at https://developer.apple.com/bug-reporting/ with preferably minimal reproduction testcase. You can also post a link to the reproduction case here