Safe mode is triggered by setting the TRILIUM_SAFE_MODE to a truthy value, usually 1.
In each artifact there is a trilium-safe-mode.sh (or .bat) script to enable it.
What it does:
- Disables 
customWidgetlauncher types inapp/widgets/containers/launcher.js. - Disables the running of 
mobileStartuporfrontendStartupscripts. - Displays the root note instead of the previously saved session.
 - Disables the running of 
backendStartup,hourly,dailyscripts and checks for the hidden subtree.