This is an extension of ISO 8859-14 for Windows CeltScript fonts. It deprecated CER-GS when this character encoding was updated in August 1998. FreeDOS calls it Code page 59620 (but the definitions may be different).
Character set
Before August 1998, the character 0x26 mapped to both & and ⁊ (Unicode character U+204A), which were unified. Before August 1998 the code point 0x80 was empty. Before August 1998, the character 0x84 mapped to ±, Unicode character U+00B1.
References