@girish This worked. What I didn't understand was that /media/name_of_volume was a hard and fast location. The documentation had this line, As a security measure, only host paths under /mnt, /media, /srv and /opt are allowed. which I took to mean that if I used any of those four + the volume name, that that was the location for the Configuration option in Nextcloud. So presumably I could still make any Volume using any of those four, but in Nextcloud the Configuration will always be /media/name_of_volume? Even though it is "now" clearly obvious in the Cloudron Nextcloud dashboard, that Apps can access mounted volumes via /media/{volume name} directory. This data is not included in the app's backup. I thought that the "/media" directory was there as an example, and that any of those four might be used, depending on how the Volume was added. But no, right there, clear as day, it says to use /media.
For someone like myself that just isn't clear and obvious. In this screenshot of adding a Volume, would it be helpful to add a line like, "These filesystem Volumes will then be accessible only at /media/name_of_volume." ? Or are there too many variables; other apps would need this specificity?
ae05db42-19c1-4b06-ad4f-621d185c230b-image.png
Or perhaps in the image shared above: Use the directory /media/{volume name}, regardless of its host path, as the path for Apps that will access mounted volumes. This data is not included in the app's backup.
I don't know.... now that I understand /media is how Cloudron manages Volumes, at least filesystem Volumes, it kind of makes sense. Thank you everyone for pitching in. The Volume did load and I can see the contents. Phew.