>I think this would better fit in `Remote.TagFetchMode`, as it describes the default value for that property.

`Remote.TagFetchMode` is not nullable, so the returned value is always well known.

In this case, however, I think it may be worth describing how the fetch operation will behave when  `FetchOptions.TagFetchMode` is unspecified and no `remote.*.tagopt` entry exists in the config.