On my iPhone, in the Apple ‘Files’ app, in the ‘Browse’ tab or section, I see “DEVONthink 4”.
If I tap it, I see a dialog with the message:
"Turn On “DEVONthink 4? To browse and add files, turn on DEVONthink 4.”
What exactly happens if I tap ‘Turn On’ in that dialog?
Does turning it on cause duplication of data? If so, would that be duplication only on my iPhone?
I currently sync databases via Dropbox, and my iPhone download settings for DEVONthink 4 are (in all cases — I think) set to ‘On Demand’, if that’s relevant.
No. That is the same as enabling a third-party cloud within the Files app, and it gives you access to DTTG’s local file system (but only to the downloaded files; they do not download automatically if you need them and are on demand). This way you can access your DTTG files from any other application.
However, do not forget to return to DTTG if you have modified something to allow the app to sync the changes.
Right. You navigate into DTTG databases and files like other filesystem (like iCloud itself, or local files) from Apps that support this way (almost all now) or the Files App itself.