Secure content not tested IV size other than 96 bits

[jordig100]

The spec says:

For the purposes of this specification, AES-GCM SHOULD be used with a 96-bit Initialization Vector (IV), 128-bit Authentication Tag (T) and it MAY contain an optional Additional Authenticated Data (AAD). The cipher text is stored in the file path defined in the parent element with the cypher file format defined in Appendix D. 3MF Cipher File Format.

This means that other IV sizes are also valid. The 96-bit is the recommended size.

[JimZuber]

The test specification does state "All test cases will use a 96 bit initialization vectors and 128 bit tags, although other lengths are allowed by the secure content specification.", so this isn't a surprise. However, it would certianly be easy to add test cases that use other initialization vector bit lengths if desired