This is supposed to be "Upwards Arrow with small triangle arrowhead: 🠁 It enters ok, lets see if it HN allows this Unicode character.
On iOS, it’s a square with a question mark inside.
Android, Firefox: Nope. It's a grey rectangle, long side horizontal.
Yes, it displays correctly in HN. Now I can submit some content that best uses UpArrow for synthesized attribute in AG. Thank you HN for supporting Unicode!
You need to test on more browsers... try https://www.browserstack.com/
It looks messed up to me on my android tablet.
It also doesn't work on my Windows 7 machine.
Firefox displays a little rectangle with "01F801" in it, and Chrome displays just an empty little rectangle. So it looks like the character doesn't appear in all Unicode fonts. (My browsers display other Unicode characters in HN comments OK, such as Chinese text.)
Chrome on Linux here, it looks fine.
Firefox on Linux now, looks fine here also.
Not on Android 9 Chrome 75