Hello. I have seen in the release notes that the new MacOS build has the capability to open external shared libraries: is there any additional info on it?
In 6.0.6 on the Mac, I put my external packages in
~/Library/Application Support/gramps/gramps60/plugins/lib
This is where I put additional packages (like idna, packaging, dbf, … ) as needed for those plugins that have dependencies on packages not in the standard distro.
EDIT: The directory is ${PYTHONUSERBASE}/lib in case your plugins are elsewhere.
Thank ! I had not thought of putting the “lib” directory in the plugins.. 
I have been using Gramps Web Sync addon since version 5.2. The Gramps AOI for Mac has never included the python keyring libraries, that the Web Sync uses (if available).
For every update of Gramps I copy the keyring libraries to the Gramps installation
/Applications/Gramps.app/Contents/Resources/lib/python3.13/site-packages/.
For new releases of Gramps would you recommend to copy these libraries to
~/Library/Application Support/gramps/gramps60/plugins/lib ?
Yes, I would recommend for Mac 6.0.6 and later to use this new location. I did what you did previously, but this is an easier solution.