Your files in other apps
On Linux
A Collection can show as an ordinary folder, for any app to open and save in: on the Collections tab, choose Mount on this computer… and pick where. Files read through it are fetched from your other devices as they’re read, so a video plays while the rest of it arrives. Files saved there are added to Iceblock, versioned like any other change.
The folder is there whenever Iceblock is running. When Iceblock restarts, for an update, apps using the folder wait until it’s back rather than failing. When Iceblock quits, the folder empties until it starts again.
On Android
Iceblock appears in the system’s file picker and Files app, so other apps can open and save your files in it.
Where it can mount
On Ubuntu, mounting is only allowed under your home folder, /mnt, /media, /tmp or /run/user/<your user id>: Ubuntu’s security rules for FUSE refuse anywhere else. iceblock mount says so if you choose somewhere else, and how to allow it there instead, if you’d rather (it needs sudo). iceblock mount --force sets it up anyway.