Users with an account and an UM printer should have some basic access to the Digital Library. To this end, and to remain future proof, the online team has made an extension to its API so now feature budgets can be gauge. At the moment it's only checked wether the user has any access to personal projects at all. If so, the interface shows Digital Library functionality. Known issue: Removing the last printer from DF while still logged in leaves the DL access in the Cura interface until logged out or Cura restarted. Additionally, I think the response for a logged in user without any printer from the API is just 'data = empty list' instead of everything set to False and 0 (which should be the case as they're all listed as required fields in their docs ... maybe I'm missing something). In any case, the code as is now can handle that as well.
CURA-8138
We want to keep it this way so people can still make plugins work for older versions of Cura, like 3.6, where the 'api' field with just a single major version, instead of the 'supported_sdk_versions', which can be either a version-string like '7.6.0' or a list of version strings.
