I'm working on an addon to automate taking screenshots of lecture slides. I'm using a canvas object to capture and save the file blobs and JSZip to zip everything together and download. But JSZip keeps throuhing the `unsupported file type` error. Even though blobs are supported. Here's the relevant code I'm using [https://github.com/JadeMaveric/patronus/blob/145ebaea8febba3241a11a220a0e30923f6b77a4/extension/content_scripts/slideshot/capture.js#L95 Github File] I've submitted an issue to the maintainer which has some more debugging info. The script in the addon_context has some very quantum behaviour and changes output every time I console.log [https://github.com/Stuk/jszip/issues/759 Github Issue] I'm wondering if there might be a problem on my end, with the way I'm generating and processing the blobs. The same code works in chromium based browser, I'm confused as to what Firefox does differently. Any help would be appreciated.