<sling:defineObjects/> tag is used in a JSP within Apache Sling, several values are added as “bindings” that are available to the JSP code. There is service interface for bindings,
BindingsValuesProvider. The question was asked by Tomek Rękawek on StackOverflow: how to add custom bindings? The answer came from the same Tomek Rękawek. The values defined by the BindingsValuesProvider are available within Sightly automatically. The value to use is
bindings. It can be used to indirectly access the value. For a more complete explanation, see StackOverFlow: How to add a custom Sling binding?