> Experimental capabilities have a little 'flask' icon next to them, and non-standard items have a little 'warning' icon next to them, mirroring MDN conventions.

This is not true. I haven’t gone through each item in detail, but there are no icons for Web Bluetooth, Web NFC, or Web USB. All of these are non-standard, Blink-only APIs that no other rendering engine has agreed to implement.

Mozilla on Web Bluetooth:

> This API provides access to the Generic Attribute Profile (GATT) of Bluetooth, which is not the lowest level of access that the specifications allow, but its generic nature makes it impossible to clearly evaluate. Like WebUSB there is significant uncertainty regarding how well prepared devices are to receive requests from arbitrary sites. The generic nature of the API means that this risk is difficult to manage. The Web Bluetooth CG has opted to only rely on user consent, which we believe is not sufficient protection. This proposal also uses a blocklist, which will require constant and active maintenance so that vulnerable devices aren't exploited. This model is unsustainable and presents a significant risk to users and their devices.

— https://mozilla.github.io/standards-positions/#web-bluetooth

Mozilla on Web NFC:

> We believe Web NFC poses risks to users security and privacy because of the wide range of functionality of the existing NFC devices on which it would be supported, because there is no system for ensuring that private information is not accidentally exposed other than relying on user consent, and because of the difficulty of meaningfully asking the user for permission to share or write data when the browser cannot explain to the user what is being shared or written.

— https://mozilla.github.io/standards-positions/#web-nfc

Mozilla on Web USB:

> Because many USB devices are not designed to handle potentially-malicious interactions over the USB protocols and because those devices can have significant effects on the computer they're connected to, we believe that the security risks of exposing USB devices to the Web are too broad to risk exposing users to them or to explain properly to end users to obtain meaningful informed consent. It also poses risks that sites could use USB device identity or data stored on USB devices as tracking identifiers.

— https://mozilla.github.io/standards-positions/#webusb

As far as I can see, you’re counting these Blink-only Google APIs as standards that other browsers are failing to implement.