Why doesn't Yubikey U2F work on fresh install of Debian 10 (buster)?

Question

After a fresh minimal install of Debian 10 (buster), I am no longer able to get my Yubikey authentication to work in web browsers. In both chrome and firefox, it times out while waiting for key. The yubikey led blinks in patterns I haven't seen before... either an intermittent short flash or on constantly. Everything in dmesg logs looks fine and matches what is described in Yubikey's documentation.

Answer 1

Turns out, this is what happens when the u2f-host package is not installed. The fix was simple:

sudo apt install u2f-host

After this package was installed, web browsers could detect and use the yubikey.