thanks, that is how my manifest file is.
In another forum (probably element?), I got the answer that at that time the temp install did not recognise the android entry
@opto, based on the error message you shared it appears that you’re trying to set "gecko_android" on the "applications" key in your extension manifest rather than "browser_specific_settings".
Firefox used to use "applications" in the manifest (and still does internally), but that value was dropped in favor of "browser_specific_settings" several years ago and no longer appears on the list of supported manifest keys.