The metadata of a zettel is a collection of key-value pairs. The syntax roughly resembles the internal header of an email (RFC5322). The key is a sequence of alphanumeric characters, a hyphen-minus character (-, U+002D) is also allowed. It begins at the first position of a new line. Uppercase letters of a key are translated to their lowercase equivalence. A key is separated from its value either by a colon character (:), a non-empty sequence of space characters, a sequence of space characters, followed by a colon, followed by a sequence of space characters. A value is a sequence of printable characters. If the value should be continued in the following line, that following line (continuation line) must begin with a non-empty sequence of space characters. The rest of the following line will be interpreted as the next part of the value. There can be more than one continuation line for a value. A non-continuation line that contains a possibly empty sequence of characters, followed by the percent sign character (%) is treated as a comment line. It will be ignored. Parsing metadata ends, if an empty line is found or if a line with at least three hyphen-minus characters is found. Some examples: title1:The Title title-2 : Another title title-3: A wrapped title title-4: A wrapped title with more than one continuation line % A comment line % Another comment line. No metadata anymore, because of the empty line.