In Abyss Web Server, the directives #echo, #exec, #fsize, #flastmod, and #include accept an optional argument encoding.
The value of this argument determines which conversion method is to be applied to the output of an XSSI directive. It can be:
none: No conversion is performed and the output is transmitted without any modification.
entity: The output is converted using the XML/HTML escaping: < is converted to <, > to >, & to &, " to ", and ' to '.
url: All non-alphanumerical characters in the output except -_.!~*'()/ are replaced with a percent sign % followed by two hexadecimal digits. This conversion conforms to the URL encoding scheme as described in RFC1738 and is useful to output well formed URLs.
reverse-url: Sequences made of a percent sign % followed by two hexadecimal digits are decoded according to the URL encoding scheme.
If no encoding argument is present in #echo, #fsize, or #flastmod directives, the server will perform entity conversion.
If the encoding argument is present in #exec or #include directives, the server will perform no conversion of the output.