That's where the top boffins of the time invented spaghetti with tomato sauce, too!

I mean…. It does and it doesn’t. Yes, al-Qarawiyyin was founded as a mosque. Yes, it became a “university” within the last 100 years. But there was a looong span of time between where it was an institution of higher learning not formally classified as a “university”

Paragraph 4 of the article you linked specifically notes that such institutions with mixed provenance were omitted from the list.

Ancient higher-learning institutions, such as those of … the Islamic world, are not included in this list owing to their cultural, historical, structural and legal differences from the medieval European university… These include the University of al-Qarawiyyin… founded as mosques in 859… These developed associated madrasas… by 1129 for al-Qarawiyyin…

Basically it is the oldest educational institution that is currently a university, as opposed to the institution having operated under the university model for the longest time.

Not long after hops became really popular as a beer ingredients. Coincidence?

Al-Qarawiyyin is recognized by UNESCO and Guinness as the world's oldest continually running institution of higher learning.