Hi Ed,
sorry for answering that late.
The resource library contracts section doesn't say anything about the FaceletCache. If we stay that vague, we are free to do whatever is necessary to implement this feature. But I think, we need multiple instances of the FaceletCache, however we implement this feature. So we should state somewhere that a developer decorating the FaceletCache, should not assume, that there is only one instance, which might seem obvious.
Writing this, I think we should have FaceletCacheWrapper.
We changed javax.faces.application.Resource#getRequestPath to include the contract name. If someone wants to decorate Resource to change getRequestPath, she might find it useful to get all necessary information. So we should add getLocalePrefix() and getResourceLibraryContract().
That's it for now.
Ciao Frank