Cryptomator integrates via File Provider API to iOS. This allows accessing individual files inside a Cryptomator vault from other apps such as the Files app. Unfortunately, the embedding and editing of entire folders located inside a Cryptomator vault via File Provider API seems to be currently not implemented. E.g. when trying to add entire folders to text editing apps such as iA Writer or Ulysses Cryptomator is greyed out:
There is an example repository from the maker of the Working Copy app demonstrating the feature: palmin/open-in-place. He further explains in this Twitter thread that to support this feature
Providers need
NSExtensionFileProviderSupportsPickingFolders=YES
in theirInfo.plist
to be included.
It would be nice if Cryptomator implements this feature as well.