Sketchpad 3.7 is the online version of Sketchpad (non packaged app).
The big advantage of this version is the availability of stamps. Like with Sketchpad 3.5 you can even create your own stamps but mouse interaction is needed to save the stamp.
Sketchpad 3.7 allows you to download in a variety of formats including Sketchpad. You can share your creation to Google Drive for cloud backup.
Sketchpad (3.7) is a great svg image editor for Chrome OS. The ability to download to an SD card or "share" to Google Drive is ideal for schools with Chromebooks.