I don't think there's a way to view the files from the app itself. You need to open the Web GUI (from the left slide-out menu) and use it to perform the operations instead. In the Web GUI, you will be able to both see what files have been locally changed, and also Syncthing will ask for confirmation before overriding the changes for real.

In other words, the app needs work, but improvements like this one are unlikely to happen unless someone steps in and implements them. I can only suggest that you should use the Web GUI instead if you want to have a full Syncthing experience.

Going to the WebGUI doesn't really make it clear for me what's going on or what my choices are:

What are those colored labels? What are my choices and how do I choose? And why do only some files have a size?

I would expect to see a list explaining the conflict (like 'changed here and remotely, file dates X and Y' and allow me to select a choice.

The labels are only informational, and they show where parts of the downloaded file come from (e.g. whether they are pulled from a remote device or reused from local files, etc.). In your case, none of that actually applies, because the folder is set to "Send Only", hence nothing is being downloaded.

Just to be clear, you cannot choose what to do regarding individual files. As the folder is set to Send Only, your only choice is to press the "override changes" button so that its content on remote devices becomes identical to the local one. If you change the type e.g. to "Send & Receive", then the button will disappear and the listed files will be downloaded to the local folder instead.

Not sure about the missing size display issue.

In sum, Syncthing at the moment doesn't offer the granular control that you want. I think there may be an open issue for that already, in the main Syncthing repository.

I thought there was an issue about having a modal dialog when clicking that button that gives some explanations of what will be the consequences. The web UI already has that dialog. I didn't find any such ticket so, so lets keep this one for that purpose (and maybe adjust button wording too - not sure).

I use this to send all pictures from my android camera to my server and desktop PC. I set up the phone as send only because the server and desktop contain the pictures from previous phones, or content from the current phone before a periodic cleanup.

In that context I would like to be able to disable or hide this action from the folder settings, so I cannot accidentally click on it. Having no confirmation dialog and being the biggest message on the screen is a very dangerous design IMHO.

I have proper backups, but still... I don't want to need to restore from them (again).

I just lost data to the lack of a confirmation dialog on the "override changes" button today. Not only did I believe it would use changes to my local copy, I expected that anything with such an effect would have a confirmation dialog that would clearly explain what would happen. Yes, it's in the docs, but I hadn't edited my setup in months, and so wasn't on guard.

This seems to have been fixed in a fork.