If you have access to the source code for these plugins, of course you could inspect it to see what they are doing. If they have defined "extensions" to OpenFlight, they will be visible on the respective "Modify Attributes Pages". For example if they have added an extension to, say, the Group node, you will see field(s) on the Group Attribute Page for their data. If they are just using OpenFlight attributes, it is difficult (if not impossible) from the outside to see which OpenFlight attributes they are using.
If you have not done so yet, you can download the OpenFlight API (which you will need to write plug-ins or scripts) from here:
Other versions are available depending on what version of Creator you intend to use your tools with.
Let us know if you have any specific questions.