[gibspaulding]

They don't seem to work in Firefox on Linux either (Ubuntu 20.04), seem to be Windows only for whatever reason.

[pwg]

The two arrows work perfectly here with Slackware 15 and Firefox 102.9.0esr.

[usr1106]

They even work on the dinosaur age Firefox in Sailfish OS. I guess it's just whether the fonts used have the character or not, nothing to do with Firefox as such.

[MayeulC]

Probably, they don't show up on Firefox Android (Fennec on LineageOS 20)

[efreak]

Might be an Android thing. They don't show up in materialistic either, a native HN client.