This files have types: *.___jb_old___ and *.___jb_bak___
The file left unchanged.
You can disable "safe write"
Use "safe write" (save changes to a temporary file first) If this check box is selected, a changed file will be first saved to a temporary file; if the save operation is completed successfully, the original file is deleted, and the temporary file is renamed.
https://www.jetbrains.com/webstorm/help/system-settings.html