(There's no video for Contextual Menu Manager (CMM) SDK yet. Please contribute to MR and add a video now!)
CMM SDK looks like a tiny collection of sample code and plugins to demonstrate how to implement Contextual Menus in Mac OS 8 applications.
CMM-SDK-1-0.3.sit (346.3 KiB / 354.61 KB)
Contextual Menu Manager SDK v1.0.3 (1998) / compressed w/ Stuffit
Sample code header and stub files... needs IDE to be compiled.
Emulating this? It should run fine under: SheepShaver