Template metadata
You can use template metadata to define constants in Page Templates, Component Templates, and Template Building Blocks, for example so that a user can define the position of a Component Presentation on a Page (that consists of two columns) by specifying a metadata property on the Component Template. You design template metadata in a Metadata Schema.
The values of template metadata are not published and can only be used within the template.
Note that if a Page Template uses a Page Schema, any metadata of the Page should be specified in the Metadata Design tab of the Page Schema of the Page.
Also note that in data publishing, Components don't use templates at all; Component Templates and Component Presentations are used only in the legacy, template-based publishing framework.