If you have a backup from a week ago, you have been editing and changing models.
How would you do the restore?
just copy the backup/{datestring}/xlights_rgbeffects.xml on top of your current xlights_rgbeffects.xml
This will take you back to how you were setup one week ago.
If you want to restore a single mode, go into an editor and look at backup/{datestring}/xlights_rgbeffects.xml and find the <model> line corresponding to the lost model.
Ctl-C to copy that model , after you highlighted the line. Exit editor and open your current xlights_rgbeffects.xml . go to the model section and paste the missing model.
You dont want to lose a weeks worth of work? Do "File,Backup" multiple times per day. Basically it gives you dozens of copies to choose from