Every plug-in has a “Manage” button with an “About” menu item in it, and in that menu is a field for “Version:”.
Currently, that can’t be used by Nyquist plug-ins, but I think it would be useful it could.
For “official” plug-ins (including plug-ins on the wiki and plug-ins shipped with Audacity), I think it would be useful to have a standard versioning scheme.
I would suggest that a suitable scheme for plug-ins could be:
(The first ‘official release’ being version 1.0.0)
“major” is incremented when there is a complete rewrite or very substantial change to code or features.
“minor” is for lesser changes that may involve code changes, algorithm changes, feature changes.
“maintenance” is for tweaks, cosmetic changes and such, that have little or no impact on end users.
Discussion of versioning schemes: https://en.wikipedia.org/wiki/Software_versioning
If this is adopted for ‘official’ plug-ins, it would also need to be in the Nyquist Plug-in documentation.