The 5 Minute Tour – Page 6
Potomac’s dirty little secret… there’s only one hardcoded metadata tag: [ExtensionPoint].
By declaring an extension point, you can create a new metadata tag that anyone can use.
The Potomac SDK FlexBuilder plugin will do syntax and property checking for your new metadata tag.
Use IBundleService#getExtensions() to find all the classes declaring your new tag. The Extension object has a full reflection API that describes the class, method, or variable where the metadata was declared.