In order to provide a description to each ZIM file that can be easily extracted we defined a special namespace M and a standardized set of keywords that should be used.
Every key is defined like an article, the key name is used as the article name, the key value is put into the article text. This way also metadata is compressed, but extendable. Further keys could be used in a ZIM file without breaking the standard but please be aware that maybe the openZIM project will define additional keys in the future. Any ZIM library reading this metadata should ignore missing keys / values and just return NULL values in such cases.
|Title||yes||title of zim file||English Wikipedia|
|Creator||yes||creator(s) of the ZIM file content||English speaking Wikipedia contributors|
|Publisher||yes||creator of the ZIM file itself||Wikipedia user Foobar|
|Date||yes||create date (ISO - YYYY-MM-DD)||2009-11-21|
|Description||yes||description of content||This ZIM file contains all articles (without images) from the english Wikipedia by 2009-11-10.|
|Language||yes||ISO639-3 language identifier||eng|
|Relation||no||URI of external related ressources|
|Source||no||URI of the original source||http://en.wikipedia.org/|
|Counter||no||Number of non-redirect entries per mime-type||image/jpeg=5;image/gif=3;image/png=2;...|
A favicon (48x48) is also mandatory and should be located at /-/favicon