schmittjoh/JMSSerializerBundle — comment on commit bf10c3ede2eb1907b756ec59114b38fc341d9d98
File: Twig/SerializerExtension.php line 45
By stof:

@schmittjoh encoding as JSON does not encode ``<`` AFAIK so in an HTML context it is not safe for instance. And in such case, saying it is safe for all formats is wrong.