Firefox sometimes changes the file extension when server sends different MIME type.

On the server side the proper MIME type should be set, or on the client side you could try to use some extension, for instance Content-Type Fixer.

Firefox sometimes changes the file extension when server sends different MIME type. On the server side the proper MIME type should be set, or on the client side you could try to use some extension, for instance Content-Type Fixer.

Would I be able to see in 'inspect' the data where Firefox is reading the file as a pdf even while it's an illustrator file? If so, where do I navigate to? I want to compare it to instances where it downloads the file type correctly.

You can find it in Developer tools in Network tab.

Thanks.

Is there a way to fix this without an extention? Like using the Firefox dev tools to tell firefox to download files from a specific trusted website not looking at MIME type rather mimicking the way chrome checks and downloads file types?

So what sites is this that the your trying to download from that is mixing up the file format? This will help others see what the sites list for the format.