Small caps
Lowercase letters as ꜱᴍᴀʟʟ ᴄᴀᴘɪᴛᴀʟꜱ.
Result
Why you would use this
Real small caps are a font feature; these are separate Unicode letters that imitate them, which is why they survive a copy-paste into a bio or a chat where no styling is allowed. Two letters have no small-cap form, so they pass through unchanged.