These links are reference sources. USL only claims a symbol is tied to a standard when the canonical symbol record contains that code.
Graphical symbols - Registered public information symbols
Reference link for ISO 7001-style public information symbols. USL records say when a symbol is linked to an ISO 7001 code present in the canonical data.
Unicode Emoji charts
Reference link for Unicode emoji codepoints used by symbol-adjacent visual communication entries.
Graphical symbols for use on equipment
Reference link for equipment graphical symbols. USL does not claim official IEC inclusion unless a symbol record explicitly links to a standard code.