smart/soft quotes are usually:
‘|’|“|”
but there are also other quoting glyphs in ASCII but especially UTF-8 ‘|’|“|”
but there are also other quoting glyphs in ASCII but especially UTF-8A PM somewhere probably thought "smart quotes" sounded neat, and here we are.
For example: 10° 33' 19" -> 10° 33« 19». Very smart!