This is related to Firefox unwilling to add support for WebUSB because, I suppose, they believe that a browser is not a general purpose application launcher and the scope of what it can do should be limited. As such, it should not be allowed to e.g. control peripherals like the USB devices.

Which is in my opinion a fairly reasonable take.

But given the current situation, I would assume that the companies providing WebUSB tools like installers would also spend a few moments to create e.g. a Python script that would do the same thing but locally. So that anyone unwilling to use WebUSB within their browser can have a vetted and transparent way to get the same thing done.

And, to counter the arguments that "the site tells you that you need WebUSB support": you get to the https://e.foundation/installer/ when you click "Check device compatibility" on the main page. Personally, I'd expect either a check that works in any browser or a simple compatible device list. Why would I need a special browser just to check if I can use this OS?

This is especially strange considering they have the list of supported devices in their docs https://doc.e.foundation/devices

So I think the issue is that the button on the main page is poorly named

Hmmm, It seems to require the WebUSB API: https://caniuse.com/?search=webusb

e/OS is not degoogled, only some of the functionality has been rewritten in microG (eg not implementing security checks but instead spoofing them), but still uses Google play sdk and libraries.

Additionally it runs in the privileged mode, so any exploit on that, well, means back luck.

Same here, they advertise with the duckduckgo browser app on the above page, but it's not supported checking compatibility.

same for grapheneos. only difference maybe that you can choose to also manually install it without WebUSB