EvtVariables are extended as EvtTopiVariables and used as runtime variable containers for any .topi extern variable.
Create one with ContextMenu > Create > Evt > Topiary > [Type]
Then set the Topi Variable Name to the name in the .topi file.
Topiary.Unity will automatically add the object to the Addressables Topiary group with labels Topiary and Evt.
Then each Dialogue will automatically load the EvtVariables and hook up callbacks with the Topiary VM.
Can be installed via the Package Manager > Add Package From Git URL...
This repo has a dependency on the EvtVariable and Topiary.Unity packages which MUST be installed first.
(From my understanding Unity does not allow git urls to be used as dependencies of packages)
https://github.com/peartreegames/evt-variables.git
https://github.com/peartreegames/topiary-unity.git
then the repo can be added
https://github.com/peartreegames/evt-topiary.git