v1.3.1 is currently pending approval.
FIXES
fixed minor save issue which occurs when the following are in effect:
the "Enable "Additional Pages media types"?" setting is enabled
the "Allow all file types?" setting is enabled
the "Allow these additional file types" setting is blank.
Workaround for the above issue: prior to saving, toggle "Allow all file types?" off, and add an entry in the "Allow these additional file types" field, then toggle "Allow all file types?" back on.