Theme metadata is specified according to ISO 15836 (Dublin Core). There appears to be no prior attempt to embed Dublin Core information into CSS, so we need to invent a method.
Each of the following should be set against the frame object with no other selectors. See the listing in Section 2 for an example.
At some point, Cowbell will check basic metadata information and refuse to load themes where it is lacking. See Section 6.8.
-dc-title: a human-readable title for this stylesheet. Example: "Sunshine".
-dc-description: a human-readable description for this stylesheet. Example: "A happy orange theme".
-dc-source: a human-readable description of the source of this stylesheet. Example: "Original stylesheet", or "Based on a Metacity theme by Daniel Borgmann".
-dc-relation: it is not clear whether this should be used to express "Requires" or "IsBasedOn". For now, assume "IsBasedOn" and give the permalink of the source theme, if any.
-dc-creator: name or URL of the theme's creator. (The Dublin Core specification says that names are preferable to URLs, but URLs seem preferable in this application.)
-dc-publisher: name or URL of the theme's publisher, if any.
-dc-rights: URL to the theme's licence.
-dc-rightsholder: name or URL of the copyright holder.
-dc-date: date of modification, in "YYYY-MM-DD" format. This serves as a version number.
-dc-identifier: a permalink for the theme.
-dc-provenance: an explanation of the reasons for the theme's existence; optional.
-dc-type: always "Software".
-dc-format: always "text/css".
-dc-subject: themes do not concern any subject.
-dc-coverage.
-dc-audience.
-dc-instructionalMethod.
-dc-accrualMethod.
-dc-accrualPeriodicy.
-dc-accrualPolicy.