It's so impressively underhandedly sneaky that Microsoft named their ODF-competitor format “Office Open” just as OpenOffice.org's (LibreOffice's direct ancestor) hype peaked with OO.o 2.0 having ODF as its native format, when MS Office finally had a viable and popular competitor for like the first time ever.
https://www.openoffice.org/press/2.0/press_release.html (2005-10-20)
https://news.microsoft.com/2005/11/21/qa-microsoft-co-sponso... (2005-11-21)