>For those who follow tl;dr religiously, the answer is: Yes it is.

You should have noted that that is not actually a tl;dr of the blog post linked to by the GP. In fact, that post comes to the opposite conclusion:

"[A] problem arose when Microsoft decided not to fully implement the Strict version of the standard in Office 2010. As published by Microsoft [...] and stated by Wikipedia [...]:

>Microsoft Office 2010 provides read support for ECMA-376, read/write support for ISO/IEC 29500 Transitional, and read support for ISO/IEC 29500 Strict.

What this means is that when you save a document in MS Office 2010 or prior in any of the ‘X’ formats, you are not saving them in the advertised OpenXML format. [...]"

Too bad no application in the world implements it.

Oh, and "implement as MS product X" isnt actually a specification.

We often complain when source code is the only real spec. But unless you are an MS employee, "implement as MS product X" comes down to reverse engineering. We dont even get the source code.

Also, if you remember back in the day .. How they even got this status .. MS was considered to be bribing institutions and blackmailing partners.

The downside of self regulation, is that messing with related institutions isnt actually illegal.