URL: https://login.live.com/

Browser / Version: Firefox Nightly 71.0a1 (2019-10-10) (64-bit)
Operating System: Windows 10
Tested Another Browser: Yes

Problem type: Site is not usable
Description: The "Sign in with a security key" option is missing
Steps to Reproduce:

1. Navigate to: https://login.live.com/
2. Observe the Login options.

Expected Behavior:
The "Sign in with a security key" option is available.

Actual Behavior:
The "Sign in with a security key" option is not available.

Notes:

1. The issue is not reproducible on Chrome.
2. Screenshot attached.

Watchers:
@softvision-oana-arbuzov
@softvision-sergiulogigan
@cipriansv

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