Frequently Asked Questions - Open XML File Formats
Q: What are you doing by adding Ecma Office Open XML to the Open Specification Promise (OSP)?
A: We are giving potential implementers of Ecma Open XML the ability to take advantage of either the covenant not to sue or the OSP, at their choice. Microsoft had already stated that it offers an irrevocable covenant not to sue to anyone wishing to implement the formats. We understand that some may prefer the new OSP, which we’d like to facilitate.
Q: Why are you applying both the covenant not to sue and the OSP? [+]
A: Some have asked whether we would apply the OSP to Ecma Office Open XML. We don’t know whether some will choose the OSP over the CNS, but we want to make that an option.