Additional priority of an XPath selector.
The XPathPriority may be used in the family configuration functions to influence which configuration will be resolved if multiple configurations collide.
A high priority makes a selector prioritized over selectors with low ones.
By default, the resolving for a configuration option compares the specificity of a number of XPath expressions. This causes specific selectors to override configuration for less specific selectors.
The priority can be used to influence this further. It can set to a value smaller than -1 or larger than 1 in order to manually specify the configuration rule's priority relative to other configuration. If priority is omitted, the specificity of the selector continues to be used. The range of priorities between -1 and 1 is reserved for future changes in the specificity-based ordering algorithm.