A Microsoft file hosting and synchronization service.
Many thanks for the update. At least this sounds like an unintentional disabling on Catalina, unlike the previous time a while back when they explicitly said it not work on High Sierra and earlier. The release notes they point to in the "useful link" say this:
**Important:**We no longer update or allow new installations of OneDrive on macOS versions older than 10.14. In order to enable OneDrive updates and new installations, we recommend updating to macOS 11.0 or newer.
Which makes it seem as if they intend it to work on 10.15 and above, although the recommendation of 11.0 or newer is unclear.
It does seem as if the Raymond Chen camp at Microsoft is definitively dead. https://www.joelonsoftware.com/2004/06/13/how-microsoft-lost-the-api-war/