That’s what I meant. Microsoft created the Office Open XML format as an open standard, but they don’t follow their own standard and make their “extended” version of the standard as the default.

Other Office suites like Libre Office support this format via strict mode, which is not selected by default when you save these files using the Microsoft Office suite.

Technically even Google does this with Chrome: Open standard JS but they also use custom components, sites that use these components break on other browsers.

Xlsx is actually an open standard, but only if you use strict mode, which Microsoft conveniently does not make the default option when saving. You have to choose it explicitly when saving.

https://en.m.wikipedia.org/wiki/Office_Open_XML

I think I need to clear a common misconception people seem to have here: Oracle has very little to do with Java.

At most, Oracle has the following connection to Java:

• Own the trademark
• Have a build of the JDK/JRE with commercial support.

However, Java as a language’s baseline comes from OpenJDK, an open source (GPL 2.0) community project which is upstream to several builds including Oracle’s JVM. It follows a “bazaar” like development model similar to the Linux kernel where you can see their mailing lists and track what’s being worked on. Anyone can contribute and the code is on Github: https://github.com/openjdk/jdk.

That being said, you don’t even need to use Oracle’s JDK (it sucks IMO) and use one of the community provided builds of OpenJDK. OpenJDK builds are provided by Eclipse, Amazon, Azul, Bellsoft and even Microsoft provides JDK/JRE builds. These are free of cost and have longer term support than Oracle’s offering.