Shared GDrive quota vs. personal GDrive quota

Sometimes one has the ability to disable specific ones (unlike disabling all). A developer once posted:

and it looks like that was its author, done after the manual was written so I’ll quote from the online help.

  --quota-warning-threshold (Integer): Threshold for warning about low quota
    Sets a threshold for when to warn about the backend quota being nearly exceeded. It is given as a percentage, and a warning is generated if the amount of available quota is less than this percentage of the total backup size. If the
    backend does not report the quota information, this value will be ignored
    * default value: 10

I don’t have such a thing, so I’m curious what it looks like. Got a description or link to documentation?
I’m disappointed that either Google is giving the wrong answer or Duplicati is asking it the wrong way.

  --quota-size (Size): A reported maximum storage
    This value can be used to set a known upper limit on the amount of space a backend has. If the backend reports the size itself, this value is ignored

You could test the above, but the help sounds like it should have no effect, as it gave the size (wrongly).
Is Destination calling this a Google Drive storage type, as opposed to going through some drive letter?