The keycap digit one emoji indicates a number 1 on a keyboard button. This symbol is mostly used rather than regular digits to count down numbers or to build dates. It will be used while dialing a number on a cell phone.
Keycap Digit One Emoji
NOTE: Keycap Digit One was accepted in 1999 as part of Unicode 3.0 and labeled Emoji 3.0 in 2016.
1️⃣ Keycap Digit One
:one: (Github, Slack)