LibreOffice has been very vocal recently, going out of its way to criticize Microsoft and its practices. Now it's speaking out again, accusing Microsoft of "deliberately" using "unnecessarily complex" file formats to exploit itsMicrosoft365 (Office) documents implement user locking.
XML is a markup language used by programs like Microsoft 365 and LibreOffice to build and define documents. As LibreOffice states:
An XML schema contains the structure, data types, and rules of an XML document and is described in an XML schema definition (XSD) file. The XSD tells the PC what to expect and checks that the data conforms to the rules. In theory, XML and XSD together form the basis of the concept of interoperability.
The two office suites take very different paths in this regard. LibreOffice uses the Open Document Format (ODF), an open standard designed not to be controlled by any one company. This format gives us text files in .odt format and spreadsheet files in .ods format.
Microsoft, on the other hand, created its own Office Open XML (OOXML) to support all features in its software, resulting in the familiar .docx and .xlsx formats. Interestingly, both formats are actually just ZIP archives. The easiest way to verify this is to take a .docx file, rename it to .zip, and unzip it. This will show you the core content of Microsoft 365 documentation.
As LibreOffice points out, XML was meant to serve as a "bridge," but Microsoft weaponized its own model, making it "so complex that it became a barrier rather than a bridge." LibreOffice likens it to a railway system where the tracks are public, but one company's control system is so complex that no other company can build compatible trains, making it nearly impossible for other companies to compete. Passengers are unaware that they are being held back by these technical barriers.
An example of this complexity includes deeply nested structures, unintuitive naming conventions, and so many optional elements that implementing this format becomes a nightmare for any non-Microsoft developer. Even a simple sentence becomes a maze of nested tags that is nearly impossible for a layperson to parse correctly, even if the results on the screen look exactly the same.
LibreOffice sees the same locking logic in other areas as well. It directly links the complex file format to the promotion of Windows 11, arguing that Microsoft has no sufficient technical reason to force users to switch, and this move seems to be just to constrain users. Because of this, it urges Windows/Office users to abandon the operating system/suite and switch to Linux/LibreOffice.