1. One or more computer-readable media devices embodying computer-readable instructions which, when executed, implement an architecture comprising: one or more attachment points each of which being configured to receive and process data associated with extension definition files that describe a software extension; an extension definition file hub structure that receives multiple extension files and merges the files to expose the files to said one or more attachment points as a single list; one or more attachment managers communicatively linked with at least one attachment point for communication that pertains to a software extension; and an attachment point manager configured to manage said one or more attachment points, the attachment point manager being further configured to: track correspondence of said one or more attachment points to one or more predicate strings contained in the data, and if the one or more predicate strings are repeated, reuse attachment points that correspond to repeated predicate strings.