doh. it’s the yubioath-flutter
package; writing out my question made me realize I was searching for yubikey
but maybe it’s only listed under yubico
… and sure enough. Kind of dissapointed there’s not some metadata that caused the app to show up for yubikey
keyword, but … whatever.
Hope this helps someone else! (and don’t forget to follow Yubikey - NixOS Wiki steps like enabling pcscd
, which the yubico article also indicates)