Project: QGIS
Version: 3.4 LTR
Temporary Scratch Layers in QGIS can be very handy when a "throw-away" layer is needed, such as when pre-processing data in multiple steps. However, they can be a trap for uniformed users who may not realise that the contents of the layer will be permanently lost when the current QGIS project is closed. Accordingly, a new indicator icon has been added which shows up next to any temporary scratch layers in the layer tree, making it immediately clear which layers are temporary only.
It's also much easier to transition these temporary layers to permanent disk-based formats. You can either click the new indicator icon or select "Make Permanent" from the layer context menu. QGIS will then prompt for a location to save the temporary layer to, then replaces it in place (keeping the same layer ID, style, form settings, etc).
