@Algot According to #Unicode NamesList.txt, it comes from the ISO 9995-7 standard.
Wikimedia has this overview of symbols from this standard: https://commons.wikimedia.org/wiki/Category:ISO_9995-7_symbols
As to how the symbol ended up in there, I do not know.
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.