[tech234a]

On iOS the page promotes the App Store version of Firefox, which is based on WebKit and doesn’t support Web Serial.

[darkwater]

Blame Apple for that.

[2Gkashmiri]

Not a full time apple user but how does third party orion browser supports Firefox addons on apple but Firefox itself doesn't support their own addons?

[tech234a]

Orion had re-implemented support for the browser extensions APIs in WebKit. Though WebKit more recently opened up its built-in addons support to third-party browsers that use it.

[2Gkashmiri]

My question is, why doesnt firefox support them

[dotproto]

Do you mean Firefox on iOS? If so, that would require the firefox-ios project to adopt BrowserEngineKit, which is relatively new. Firefox for iOS WebExtension support is being tracked in https://bugzilla.mozilla.org/show_bug.cgi?id=1497374