The weirdness is partly in JSON . In the JSON spec, the slash (named "solidus" there) is the only character that can be written plainly or prefixed with a backs

The weirdness is partly in JSON . In the JSON spec, the slash (named "solidus" there) is the only character that can be written plainly or prefixed with a backslash (AKA "reverse solidus"). See page 4, section 9 of the latest ECMA for JSON: https://ecma-international.org/wp-content/uploads/ECMA-404_2nd_edition_december_2017.pdf https://ecma-international.org/wp-content/uploads/ECMA-404_2...