Why does Adaptavist ThemeBuilder - Engine and Adaptavist ThemeBuilder - Editor have differe versions

[Tara Martucci]

I am using Confluence data center. Why does my installed plugin Adaptavist ThemeBuilder - Engine and Adaptavist ThemeBuilder - Editor have different versions ? I have Version: 5.8.4 for Adaptavist ThemeBuilder - Editor. Then, for Adaptavist ThemeBuilder - Engine I have Version:1.7.29.  Can someone explain why it is this way ?