Die Document Foundation kritisiert die EU-Kommission für die ausschließliche Nutzung von Microsofts XLSX-Format bei der Cyber-Resilience-Act-Konsultation.
Although XLSX is standardized as OOXML according to ISO/IEC 29500, Microsoft’s implementations often deviate from the specifications. Furthermore, features often change undocumented, which complicates compatibility with open-source software such as LibreOffice.
https://www.iso.org/standard/71691.html
Not as proprietary as one may think, but definitely a way for indoctrination by Microsoft and therefore problematic
From the article
Yes, i always wonder about that