This closes #1889, refs #1732 and #1735 (#1890)

[barlevd]

Saving workbook with reverse sorted internal part path to keep same hash of identical files and fix incorrect MIME type

PR Details

Description

Related Issue

Motivation and Context

How Has This Been Tested

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.