XUL was conceived by Dave Hyatt FOR Mozilla AT Netscape. Netscape was going to end development of not-Windows Mozilla because maintaining 3 front-end teams was more than the Netscape/Mozilla leadership believed it had resources for and XPFE was the solution.

If you believe XUL was developed for anything other than Mozilla's XPFE, you have been mislead.

Also, would you please provide names for those many pre-XUL XML-based UI languages I'm genuinely curious. Other than the web itself, HTML+JS+CSS, I'm at a loss for what those many XML-based UI markup languages you're referring to could possibly be. As a Mozilla participant at Netscape, and someone with hours of discussion with Hyatt over those early years, and a (very small) contributor to XPFE as early as Dave's XUL menus first draft, I'd be real interested to learn about prior art. Did we somehow miss all of those per-existing examples?

XUL was created by Netscape employees for Netscape's XPToolkit project¹. I didn't think that saying that "Mozilla² adopted XUL" would be considered controversial or somehow denigrating, so apologies if if came off that way.

AOL acquired Netscape in 1999, then became the first company to ship XUL as part of Netscape 6 in 2000. https://en.wikipedia.org/wiki/Netscape_6#:~:text=With%20publ... AOL abandoned XUL to the Mozilla open source community not long after, when they disbanded the Netscape team in 2003.²

> Also, would you please provide names for those many pre-XUL XML-based UI languages I'm genuinely curious.

WML, XFDL, and Glade XML all shipped in 1998, two years before Netscape 6. Adobe's XFA also shipped before Netscape 6.

¹ https://www-archive.mozilla.org/xpfe/whoswho ² at the time meaning, "the software suite formerly known as Netscape Communicator" ³ https://www.mentalfloss.com/article/502789/day-2003-netscape...