Correct on the clevis connection method. Below is a modified copy of the above diagram showing where the extension end with the spring goes when assembled on the backing plate. When the cable is pulled forward with the pedal pressed, it pulls the lever forward at the cable clevis connection, the lever pivoting on the eccentric (adjusting) bolt that attaches it to the rear show. The lever is forced forward pressing against the extension (lever meets extension in the groove of the extension with spring surrounding the extension rod and contacting against the lever) which spread the shoes out against the drum to cause the braking action.
More later on the individual part info.
