BOOTCDN: https://www.bootcdn.cn/
BootCDN is a free CDN service for front-end open-source projects jointly supported and maintained by JiTu Cloud (极兔云) and the Bootstrap Chinese Site (Bootstrap中文网), dedicated to providing stable, fast, free CDN acceleration for front-end open-source projects as excellent as Bootstrap, jQuery, React and Vue.js. The open-source projects collected by BootCDN are mainly synchronized from the cdnjs open-source project repository.
Since going live in 2013, it has provided stable, reliable free CDN acceleration for close to a million websites.
As of now it has collected a total of 4060 front-end open-source projects.